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Chapitre 1

Numbers and Numerals

Lecture : 27 minQuiz de 16 questions

# Numbers and Numerals ## First contact and diagnostic assessment ### Introduction Welcome to your first mathematics lesson in Form One! Today, we're going to start by exploring the foundational concepts of numbers and numerals. This lesson is designed to help us understand what you already know about these topics and to identify any areas where you might need a bit more support. Don't worry if you don't know everything; that's why we're here to learn! ### Key Concepts #### What are Numbers? A **number** is an idea or an abstract concept that represents a quantity or an amount. For example, when you think of "three apples," the "three" is the number, representing the quantity of apples. #### What are Numerals? A **numeral** is a symbol or a group of symbols used to represent a number. It's how we write down the idea of a number. So, the symbol `3` is a numeral that represents the number three. The word "three" is also a numeral. #### Digits Digits are the basic building blocks of numerals. In our common number system (the decimal system), we use ten digits: \(0, 1, 2, 3, 4, 5, 6, 7, 8, 9\). #### Place Value **Place value** is the value of a digit based on its position in a number. In our decimal system, each position has a value ten times greater than the position to its right. For example, in the number \(345\): * The digit `5` is in the **Units** place (or Ones place), so its value is \(5 \times 1 = 5\). * The digit `4` is in the **Tens** place, so its value is \(4 \times 10 = 40\). * The digit `3` is in the **Hundreds** place, so its value is \(3 \times 100 = 300\). #### Reading and Writing Numbers To read and write large numbers, we group digits into sets of three, starting from the right. These groups are called periods (e.g., thousands, millions, billions). Example: Reading the number \(456,789\) * `456` is in the thousands period, so we read "four hundred fifty-six thousand." * `789` is in the units period, so we read "seven hundred eighty-nine." * Together: "Four hundred fifty-six thousand, seven hundred eighty-nine." #### Types of Numbers (Introduction) ##### Natural Numbers **Natural numbers** are the counting numbers. They are \(1, 2, 3, 4, ...\) and so on, extending infinitely. They are often represented by the symbol \( \mathbb{N} \). ##### Whole Numbers **Whole numbers** include all natural numbers and zero. They are \(0, 1, 2, 3, 4, ...\) and so on. They are often represented by the symbol \( \mathbb{W} \). ### Vocabulary * **Number:** An idea of quantity or amount. * **Numeral:** A symbol or group of symbols representing a number. * **Digit:** A single symbol used to write numbers (\(0, 1, 2, ..., 9\)). * **Place Value:** The value of a digit based on its position in a number. * **Natural Numbers:** Counting numbers (\(1, 2, 3, ...\)). * **Whole Numbers:** Natural numbers including zero (\(0, 1, 2, 3, ...\)). * **Decimal System:** Our number system based on ten, using ten digits (0-9). ### Examples 1. **Identify Numbers and Numerals:** * The number of fingers on one hand is `5`. Here, `5` is the **numeral** representing the **number** five. * The statement "There are *seven* days in a week." Here, "seven" is the **numeral** representing the **number** seven. 2. **Place Value:** * In the number \(7,421\): * The digit `1` is in the Units place (value \(1 \times 1 = 1\)). * The digit `2` is in the Tens place (value \(2 \times 10 = 20\)). * The digit `4` is in the Hundreds place (value \(4 \times 100 = 400\)). * The digit `7` is in the Thousands place (value \(7 \times 1000 = 7000\)). 3. **Reading and Writing Numbers:** * Write the number `23,509` in words: "Twenty-three thousand, five hundred nine." * Write "One hundred two thousand, forty-five" in figures: `102,045`. ### Exercises 1. For the number \(86,132\): a. What is the place value of the digit `6`? b. What is the value of the digit `1`? c. Write the number in words. 2. Write the following numbers in figures: a. Fifty-four thousand, three hundred one b. Seven hundred nine thousand, two hundred fifty-six 3. Write the following numbers in words: a. \(9,876\) b. \(304,115\) 4. Which of the following are natural numbers? \(0, 5, -2, 100, \frac{1}{2}\) 5. Which of the following are whole numbers? \(0, 5, -2, 100, \frac{1}{2}\) ### Assignment 1. For the number \(735,081\): a. What is the place value of the digit `0`? b. What is the value of the digit `7`? c. Write the number in words. 2. Write the following numbers in figures: a. Two hundred six thousand, one hundred eight b. Nine hundred thousand, four hundred fifty 3. Write the following numbers in words: a. \(12,345\) b. \(567,890\) 4. Give two examples of a natural number and two examples of a whole number. 5. Explain the difference between a number and a numeral using your own words and an example. ### Summary Today, we started our journey into mathematics by understanding the basic difference between **numbers** (the idea of quantity) and **numerals** (the symbols we use to write them). We learned about **digits**, and the crucial concept of **place value** which helps us understand the value of each digit in a number. We also practised reading and writing numbers and had a brief introduction to **natural numbers** and **whole numbers**. This diagnostic lesson helps us identify what you already know, and we will build on these foundations in future lessons! ## The history and evolution of numbers. ### Introduction Welcome to an exciting journey into the past! Have you ever wondered where numbers came from? Or how people counted before they had numbers like 1, 2, 3? For many thousands of years, humans have needed to count things: how many animals they hunted, how many days until the next full moon, or how many people were in their tribe. This lesson will explore how numbers started and how they changed over time to become the system we use today. ### Key Concepts #### Early Counting Methods Long ago, people didn't have numbers as we know them. They used simple ways to keep track of quantities. * **Tally Marks:** This was one of the earliest forms of counting. People would make marks on bones, wood, or even cave walls to represent items. Each mark stood for one item. For example, to count five sheep, they would make five marks: | * **Body Parts:** People used their fingers, toes, and other body parts to count. Some cultures even used different parts of the arm or leg to count higher numbers. * **Stones and Knots:** Sometimes, people would use small stones or tie knots in ropes to keep track of quantities. One stone or one knot could represent one item. #### Ancient Number Systems As societies grew, they needed more advanced ways to count and record numbers. Different civilizations developed their own unique number systems. ##### Egyptian Hieroglyphic Numerals The ancient Egyptians used pictures (hieroglyphs) to represent numbers. They had symbols for 1, 10, 100, and so on. For example: * A single stroke | for 1 * A heel bone \( \cap \) for 10 * A coil of rope \( \odot \) for 100 ##### Roman Numerals Many of you might have seen Roman numerals on clocks or in book chapters. The ancient Romans used letters from their alphabet to represent numbers. Here are some basic ones: * I = 1 * V = 5 * X = 10 * L = 50 * C = 100 * D = 500 * M = 1000 Roman numerals use addition and subtraction rules. For example, VI means \( 5 + 1 = 6 \), while IV means \( 5 - 1 = 4 \). ##### The Hindu-Arabic Numeral System This is the system we use today! It originated in India and was later spread to the Western world by Arab mathematicians. It is also known as the **decimal system** because it is based on ten (deci means ten). ###### Key Features: * **Digits:** It uses ten unique digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. * **Place Value:** The position of a digit in a number determines its value. For example, in the number 345: * The 5 is in the ones place, meaning \( 5 \times 1 = 5 \) * The 4 is in the tens place, meaning \( 4 \times 10 = 40 \) * The 3 is in the hundreds place, meaning \( 3 \times 100 = 300 \) * So, \( 345 = 300 + 40 + 5 \) * **The Invention of Zero:** The concept of zero (0) was a groundbreaking invention. It acts as a placeholder, allowing us to distinguish between numbers like 4, 40, and 400. Without zero, a place value system would not work properly. ### Vocabulary * **Numeral:** A symbol or sign used to represent a number. For example, '3' is a numeral, 'III' is a numeral. * **Number System:** A set of symbols and rules for counting and representing numbers. * **Tally Marks:** Simple lines or strokes used for counting, where each mark represents one item. * **Place Value:** The value a digit has because of its position in a number. * **Zero (0):** A number that means 'nothing' or 'none'. It is crucial in our place value system as a placeholder. ### Examples 1. **Counting with Tally Marks:** If you count 7 apples, you would use tally marks like this: ||| 2. **Roman Numerals:** * To write 12 in Roman numerals: \( X + II = XII \) * To write 40 in Roman numerals: \( L - X = XL \) * To write 156 in Roman numerals: \( C + L + VI = CLVI \) 3. **Hindu-Arabic Place Value:** In the number 528: * The digit 8 is in the ones place (value = 8). * The digit 2 is in the tens place (value = 20). * The digit 5 is in the hundreds place (value = 500). ### Exercises 1. Represent the number 9 using tally marks. 2. Write the following Roman numerals in Hindu-Arabic numerals: a) VII b) XXIX c) LXV 3. Write the following Hindu-Arabic numerals in Roman numerals (using basic letters I, V, X, L, C): a) 8 b) 14 c) 72 4. What is the place value of the underlined digit in each number? a) 4\( \underline{5} \)1 b) \( \underline{8} \)03 c) 17\( \underline{0} \)9 5. Why is the number zero so important in our number system? ### Assignment 1. Research and write down two advantages of the Hindu-Arabic numeral system compared to the Roman numeral system. 2. Find out about another ancient number system (e.g., Mayan, Babylonian, Chinese) and describe one interesting feature about it. 3. Write the year you were born in Roman numerals. ### Summary Today, we traveled through time to see how numbers evolved. We started from simple tally marks and the use of body parts for counting. We then learned about ancient systems like Egyptian and Roman numerals, which had their own symbols and rules. Finally, we explored the amazing Hindu-Arabic system, which we use daily. Remember the importance of its ten digits, the concept of place value, and the groundbreaking invention of zero. This system makes counting, calculating, and understanding large numbers much easier and more efficient! ## Egyptian and Roman numerals ### Introduction Welcome to our lesson on ancient number systems! For thousands of years, people have needed ways to count and record quantities. Before our modern number system (which uses digits 0-9), different civilizations developed their own unique ways to write numbers. Today, we will explore two fascinating systems: the Egyptian numerals and the Roman numerals. Understanding these systems helps us appreciate the history of mathematics and how our current number system evolved. ### Key Concepts #### Egyptian Numerals The ancient Egyptians used a system of hieroglyphs (picture symbols) to represent numbers. Their system was primarily additive, meaning you added the values of the symbols together to get the total number. ##### Symbols and Values Here are the basic symbols used by the ancient Egyptians and their corresponding modern values: * **Single Stroke (Staff)**: 1 * **Heel-bone**: 10 * **Coil of Rope**: 100 * **Lotus Flower**: 1,000 * **Pointing Finger**: 10,000 * **Tadpole or Fish**: 100,000 * **Astonished Man**: 1,000,000 ##### Rules for Writing Egyptian Numerals 1. **Additive Principle**: The value of a number is found by adding the values of all its symbols. 2. **Repetition**: Symbols could be repeated up to nine times. For example, three strokes represent 3 (1 + 1 + 1). 3. **No Place Value**: Unlike our modern system where the position of a digit matters (e.g., the '2' in 20 is different from '2' in 2), the order of Egyptian numeral symbols did not change their value. However, they usually wrote symbols of higher value before symbols of lower value for clarity. ##### Examples of Egyptian Numerals * **To write 3**: Staff, Staff, Staff (|||) * **To write 24**: Heel-bone, Heel-bone, Staff, Staff, Staff, Staff (∩∩||||) * **To write 123**: Coil of rope, Heel-bone, Heel-bone, Staff, Staff, Staff (ⱹ∩∩|||) * **To write 1,321**: Lotus flower, Coil of rope, Coil of rope, Coil of rope, Heel-bone, Heel-bone, Staff (𓆸ⱹⱹⱹ∩∩|) #### Roman Numerals Roman numerals were used by the ancient Romans and are still seen today in some places like clock faces, book chapters, and movie copyrights. This system uses letters from the Latin alphabet to represent numerical values. ##### Symbols and Values Here are the basic Roman numeral symbols and their corresponding modern values: * **I**: 1 * **V**: 5 * **X**: 10 * **L**: 50 * **C**: 100 * **D**: 500 * **M**: 1,000 ##### Rules for Writing Roman Numerals 1. **Additive Rule**: When a symbol of equal or smaller value is placed after a symbol of greater value, you add their values. * Example: VI = 5 + 1 = 6 * Example: LX = 50 + 10 = 60 2. **Subtractive Rule**: When a symbol of smaller value is placed *before* a symbol of greater value, you subtract the smaller value from the greater value. This rule only applies to specific pairs: * IV = 5 - 1 = 4 * IX = 10 - 1 = 9 * XL = 50 - 10 = 40 * XC = 100 - 10 = 90 * CD = 500 - 100 = 400 * CM = 1000 - 100 = 900 3. **Repetition Rule**: * Symbols I, X, C, and M can be repeated up to three times to represent their values. Example: III = 3, XX = 20, CCC = 300. * Symbols V, L, and D are never repeated. 4. **Order**: Generally, larger values are placed to the left of smaller values, but the subtractive rule is an exception. ##### Examples of Roman Numerals * **To write 7**: VII (5 + 1 + 1) * **To write 19**: XIX (10 + (10 - 1)) * **To write 45**: XLV ((50 - 10) + 5) * **To write 99**: XCIX ((100 - 10) + (10 - 1)) * **To write 2024**: MMXXIV (1000 + 1000 + 10 + 10 + (5 - 1)) ### Vocabulary * **Numeral**: A symbol or group of symbols that represents a number. For example, '7' is a numeral, and 'VII' is a numeral. * **Number System**: A set of symbols and rules for combining them to represent numbers. * **Hieroglyphs**: A form of writing using pictures and symbols, used by the ancient Egyptians. * **Additive Principle**: A rule in number systems where the total value is found by adding the values of individual symbols. * **Subtractive Principle**: A rule in some number systems where a smaller value symbol placed before a larger value symbol indicates subtraction. ### Examples Let's work through some conversions together: 1. **Convert 248 to Egyptian Numerals.** * Break down 248: 2 hundreds, 4 tens, 8 ones. * Egyptian: Coil of rope, Coil of rope, Heel-bone, Heel-bone, Heel-bone, Heel-bone, Staff, Staff, Staff, Staff, Staff, Staff, Staff, Staff (ⱹⱹ∩∩∩∩||||||||) 2. **Convert the Egyptian Numeral 𓆸𓆸ⱹ∩∩|| to a modern number.** * 𓆸 (Lotus flower) = 1,000 * 𓆸 (Lotus flower) = 1,000 * ⱹ (Coil of rope) = 100 * ∩ (Heel-bone) = 10 * ∩ (Heel-bone) = 10 * | (Staff) = 1 * | (Staff) = 1 * Total: 1000 + 1000 + 100 + 10 + 10 + 1 + 1 = **2122** 3. **Convert 1994 to Roman Numerals.** * Break down 1994: 1000 + 900 + 90 + 4 * 1000 = M * 900 = CM (1000 - 100) * 90 = XC (100 - 10) * 4 = IV (5 - 1) * Roman Numeral: **MCMXCIV** 4. **Convert MCMLXXXVII to a modern number.** * M = 1000 * CM = 900 (1000 - 100) * L = 50 * XXX = 30 (10 + 10 + 10) * VII = 7 (5 + 1 + 1) * Total: 1000 + 900 + 50 + 30 + 7 = **1987** ### Exercises Try these on your own! 1. Convert the following modern numbers to Egyptian Numerals: a. 15 b. 102 c. 2,314 2. Convert the following Egyptian Numerals to modern numbers: a. ∩||| b. ⱹⱹ∩∩∩|| c. 𓆸𓆸𓆸ⱹⱹⱹⱹ∩∩∩∩∩∩∩|||| 3. Convert the following modern numbers to Roman Numerals: a. 8 b. 39 c. 245 d. 1492 4. Convert the following Roman Numerals to modern numbers: a. XIII b. XXIV c. DLX d. MCDXLIV ### Assignment Continue practicing at home! These questions will help you become an expert. 1. Convert the year you were born into both Egyptian and Roman numerals. 2. What is the largest number you can write using only three different Roman numeral symbols? 3. Write the number of days in a year (365) using both Egyptian and Roman numerals. 4. If an ancient Roman wanted to write the number 600, what would it look like? 5. Explain in your own words the main difference between how Egyptian and Roman numerals use repetition of symbols. ### Summary Today, we explored two ancient number systems: Egyptian and Roman numerals. Egyptian numerals used hieroglyphs and an additive principle, where symbols were simply added together, and their order didn't affect the value. Roman numerals used letters, combining an additive principle with a special subtractive rule for certain pairs to represent numbers more efficiently. While both systems were important in their time, they can be quite complex compared to our modern place-value system, which makes calculations much easier. Understanding these historical systems shows us the diverse ways humans have developed to count and record the world around them. ## Hindu-Arabic numerals and place value ### Introduction Welcome to our lesson on **Hindu-Arabic numerals and place value**! In this lesson, we will explore the number system we use every day, understand what digits are, and learn how the position of a digit in a number changes its value. This is a fundamental concept in mathematics that will help you read, write, and understand large numbers. ### Key Concepts #### What are Hindu-Arabic Numerals? Hindu-Arabic numerals are the ten symbols we use to write all numbers. They are: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. This system originated in India and was later adopted and spread by Arab mathematicians. It is now the most common system used worldwide. #### Digits * Each of the ten symbols (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) is called a **digit**. * Numbers are formed by combining these digits. * For example, the number 25 is made up of two digits: 2 and 5. * The number 1,347 is made up of four digits: 1, 3, 4, and 7. #### Place Value System The Hindu-Arabic numeral system is a **place value system**. This means that the value of a digit depends on its position (or 'place') within a number. As we move from right to left in a number, each place represents a value ten times greater than the place to its right. #### Understanding Place Value Let's look at the different places in a number: * **Units (or Ones) Place:** The rightmost digit represents the number of ones. * **Tens Place:** The digit to the left of the units place represents the number of tens. * **Hundreds Place:** The digit to the left of the tens place represents the number of hundreds. * **Thousands Place:** The digit to the left of the hundreds place represents the number of thousands. * **Ten Thousands Place:** The digit to the left of the thousands place represents the number of ten thousands. * **Hundred Thousands Place:** The digit to the left of the ten thousands place represents the number of hundred thousands. We can continue this pattern for millions, ten millions, hundred millions, and so on. #### Value of a Digit The **value** of a digit in a number is determined by multiplying the digit itself by its place value. * For example, in the number 345: * The digit 5 is in the units place, so its value is \( 5 \times 1 = 5 \). * The digit 4 is in the tens place, so its value is \( 4 \times 10 = 40 \). * The digit 3 is in the hundreds place, so its value is \( 3 \times 100 = 300 \). #### Writing Numbers in Words To write a number in words, we read the number from left to right, grouping digits in threes from the right (thousands, millions, etc.) and using the appropriate place value names. #### Writing Numbers in Figures To write a number in figures, we listen for the place value names and place the digits in their correct positions. Remember to use zeros as placeholders if a particular place value is empty. #### Expanded Form The expanded form of a number shows the sum of the values of each of its digits. For example, the number 345 can be written in expanded form as \( 300 + 40 + 5 \). ### Vocabulary * **Numeral:** A symbol or group of symbols that represents a number. * **Digit:** Any of the ten symbols (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) used to write numbers. * **Place Value:** The value of a digit based on its position in a number. * **Value:** The actual amount a digit represents in a number, determined by the digit multiplied by its place value. * **Hindu-Arabic Numerals:** The number system using the ten digits (0-9) and a place value system, which is the most common number system used today. ### Examples **Example 1: Identify Place Value and Value** For the number **5,283**: * What is the place value of the digit '2'? * **Solution:** The digit '3' is in the units place, '8' in the tens place, '2' in the hundreds place, and '5' in the thousands place. So, the place value of '2' is **Hundreds**. * What is the value of the digit '5'? * **Solution:** The digit '5' is in the thousands place. Its value is \( 5 \times 1000 = 5000 \). **Example 2: Write a Number in Words** Write the number **4,706** in words. * **Solution:** Four thousand, seven hundred and six. **Example 3: Write a Number in Figures** Write "Fifty-two thousand, one hundred and fifteen" in figures. * **Solution:** 52,115 **Example 4: Write a Number in Expanded Form** Write the number **7,309** in expanded form. * **Solution:** \( 7000 + 300 + 0 + 9 \) or \( 7000 + 300 + 9 \) ### Exercises 1. For the number **9,417**: a. What is the place value of the digit '4'? b. What is the value of the digit '9'? c. What is the value of the digit '1'? 2. Write the following numbers in words: a. 3,568 b. 12,045 c. 70,003 3. Write the following numbers in figures: a. Six thousand, two hundred and ninety-one b. Forty-five thousand, seven hundred c. One hundred thousand, eight hundred and two 4. Write the following numbers in expanded form: a. 632 b. 5,810 c. 23,456 ### Assignment 1. Identify the place value of the underlined digit in each number: a. 4\_\_**8**\_\_2 b. **7**\_\_0\_\_1\_\_5 c. 2\_\_4\_\_**6**\_\_9\_\_0 2. Write the numerical value for the following: a. Seven hundreds b. Three thousands and five tens c. Two ten thousands and nine units 3. What is the difference in value between the two '3's in the number 3,437? 4. A school has a total of five thousand, two hundred and ten students. Write this number in figures. 5. Using only the digits 1, 0, 5, and 8, what is the largest four-digit number you can form? What is the smallest? ### Summary Today, we learned about the **Hindu-Arabic numeral system**, which uses ten digits (0-9). We discovered that this system is based on **place value**, meaning the position of a digit determines its value. We practiced identifying place values, calculating the value of a digit, and writing numbers in both words and figures, as well as in **expanded form**. Understanding place value is crucial for all future mathematical concepts! ## Numbers in words and in figures ### Introduction Welcome to our lesson on Numbers in Words and in Figures! In our daily lives, we use numbers for counting, measuring, and identifying things. Sometimes we write numbers using digits (like 1, 2, 3), and other times we write them out using words (like "one," "two," "three"). In this lesson, we will learn how to confidently convert numbers from figures to words and from words back to figures, understanding the value of each digit. ### Key Concepts #### Understanding Digits Digits are the basic symbols we use to write numbers. There are ten digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. #### Place Value Place value is the value of each digit in a number based on its position. Each position has a specific value. As you move to the left, the value of the place increases by ten times. Let's look at the place values we will focus on: * **Ones** (or Units): The rightmost digit. Its value is the digit itself. (e.g., in 3, the 3 is in the Ones place) * **Tens**: The second digit from the right. Its value is the digit multiplied by ten. (e.g., in 30, the 3 is in the Tens place, meaning 3 tens or 30) * **Hundreds**: The third digit from the right. Its value is the digit multiplied by one hundred. (e.g., in 300, the 3 is in the Hundreds place, meaning 3 hundreds or 300) * **Thousands**: The fourth digit from the right. Its value is the digit multiplied by one thousand. * **Ten Thousands**: The fifth digit from the right. Its value is the digit multiplied by ten thousand. * **Hundred Thousands**: The sixth digit from the right. Its value is the digit multiplied by one hundred thousand. * **Millions**: The seventh digit from the right. Its value is the digit multiplied by one million. **Example:** In the number 5,432,100 * 5 is in the Millions place (5,000,000) * 4 is in the Hundred Thousands place (400,000) * 3 is in the Ten Thousands place (30,000) * 2 is in the Thousands place (2,000) * 1 is in the Hundreds place (100) * 0 is in the Tens place (0) * 0 is in the Ones place (0) #### Reading and Writing Numbers in Words (Word Form) To write numbers in words, we read the digits from left to right, identifying the place value of each group of three digits (called a period). 1. **Read in groups of three:** Starting from the right, group the digits in threes. These groups are called periods: Ones, Thousands, Millions, and so on. * Example: 123,456,789 * 789 is the Ones period. * 456 is the Thousands period. * 123 is the Millions period. 2. **Read each group:** Read the numbers in each period, and then state the period's name. * **Rule for hyphens:** Use a hyphen between the tens and ones digits when writing numbers from twenty-one to ninety-nine (e.g., thirty-five, seventy-two). * **Rule for "and":** In British English, "and" is used between the hundreds and the tens/units digits in a whole number (e.g., one hundred and fifty-three). We will follow this convention. **Examples:** * **15:** Fifteen * **42:** Forty-two * **105:** One hundred and five * **367:** Three hundred and sixty-seven * **2,450:** Two thousand, four hundred and fifty * **15,309:** Fifteen thousand, three hundred and nine * **723,000:** Seven hundred and twenty-three thousand * **1,000,000:** One million * **5,678,901:** Five million, six hundred and seventy-eight thousand, nine hundred and one #### Writing Numbers in Figures (Standard Form) To write numbers from words to figures, you need to understand place value and use commas correctly. 1. **Identify the periods:** Look for words like "thousand," "million," etc., to identify the different periods in the number. 2. **Write digits for each period:** For each period, write the digits in the correct place value. 3. **Use zeros as placeholders:** If a place value is empty, use a zero (0) as a placeholder. 4. **Use commas:** Use commas to separate the periods (e.g., after the thousands and millions). **Examples:** * **Fifty-seven:** 57 * **One hundred and twenty-three:** 123 * **Three hundred and four:** 304 * **Six thousand, eight hundred and one:** 6,801 * **Forty-five thousand, two hundred and ten:** 45,210 * **Nine hundred thousand, five hundred and fifty:** 900,550 * **Two million, one hundred thousand, seventy-five:** 2,100,075 ### Vocabulary * **Digit:** Any of the ten symbols (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) used to write numbers. * **Numeral:** A symbol or group of symbols that represents a number; a number written in figures. * **Place Value:** The value of a digit based on its position in a number. * **Standard Form (Figures):** The common way of writing numbers using digits (e.g., 5,432). * **Word Form (Words):** Writing a number using words (e.g., five thousand, four hundred and thirty-two). * **Period:** A group of three digits in a large number, separated by commas (e.g., the thousands period, the millions period). ### Examples 1. **Question:** Write the number 7,045 in words. * **Solution:** Seven thousand, forty-five. 2. **Question:** Write the number 345,678 in words. * **Solution:** Three hundred and forty-five thousand, six hundred and seventy-eight. 3. **Question:** Write the number 9,002,150 in words. * **Solution:** Nine million, two thousand, one hundred and fifty. 4. **Question:** Write "Eight hundred and nineteen" in figures. * **Solution:** 819 5. **Question:** Write "Sixty-three thousand, one hundred and seven" in figures. * **Solution:** 63,107 6. **Question:** Write "Four million, twenty thousand, five hundred and thirty-six" in figures. * **Solution:** 4,020,536 ### Exercises 1. Write the following numbers in words: a. 98 b. 512 c. 4,076 d. 12,345 e. 250,900 f. 7,000,000 g. 8,000,105 2. Write the following numbers in figures: a. Thirty-seven b. Two hundred and sixty-one c. Nine hundred and two d. Five thousand, one hundred and twelve e. Eighteen thousand, five hundred f. Three hundred and forty thousand, one hundred and seven g. Six million, seven hundred and fifty thousand, nine hundred and two 3. What is the place value of the digit '6' in the number 167,890? 4. What is the value of the digit '2' in the number 4,235,100? ### Assignment 1. Write the following numbers in words: a. 101 b. 999 c. 1,500 d. 34,000 e. 705,321 f. 1,234,567 g. 5,010,001 2. Write the following numbers in figures: a. Ninety-five b. Seven hundred and eight c. Four thousand, six hundred and thirty d. Fifty-two thousand, nine hundred and fourteen e. One hundred and ten thousand, four hundred and one f. Two million, five hundred thousand g. Ten million, eight hundred and seventy-six thousand, three hundred and twenty-one 3. Explain in your own words why place value is important when writing numbers. ### Summary Today, we learned about the two main ways to represent numbers: in **figures (standard form)** and in **words (word form)**. We discovered the importance of **place value**, where the position of a digit determines its worth (Ones, Tens, Hundreds, Thousands, Millions, etc.). We practised converting numbers from figures to words by grouping digits into periods and using "and" appropriately for whole numbers in words. We also converted numbers from words to figures, remembering to use zeros as placeholders and commas to separate periods for clarity. Understanding these concepts helps us read, write, and work with numbers more effectively in mathematics and in everyday life.

Quiz du chapitre

16 questions — vérifie chaque réponse pour voir l'explication.

  1. 1. What was one of the earliest methods used by humans to keep track of quantities before written numerals existed?
  2. 2. Which ancient civilization developed a numeral system that used hieroglyphic symbols, such as a staff for one and a heel bone for ten?
  3. 3. The Roman numeral system (e.g., I, V, X, L, C, D, M) is primarily known for being:
  4. 4. Which numeral system is the foundation for the number system we use worldwide today, featuring digits 0-9 and a place-value system?
  5. 5. The crucial concept of 'zero' as both a number and a placeholder was developed independently by which two ancient cultures?
  6. 6. In the number 723, the '7' represents 7 hundreds because of its position. This characteristic of a number system is called:
  7. 7. Our modern number system is a base-10 system. What does 'base-10' primarily mean?
  8. 8. Which ancient civilization's number system used a base-60 (sexagesimal) system and cuneiform wedge-shaped marks on clay tablets?
  9. 9. What is a major advantage of the Hindu-Arabic numeral system over earlier systems like Roman numerals?
  10. 10. What is the primary difference between a 'number' and a 'numeral'?
  11. 11. Before numbers were written, people sometimes used small stones or pebbles for counting. What is the origin of the word 'calculate'?
  12. 12. Which set of symbols represents Roman numerals?
  13. 13. The development of a base-10 system, including the use of zero and place value, is largely attributed to which group of scholars?
  14. 14. What is a key feature of a 'positional number system'?
  15. 15. The Mayan numeral system was unique for its use of a base-20 system and which symbol to represent zero?
  16. 16. Which of the following is an example of an early counting tool that involved tying knots in ropes?