Mathematics Class 3 - Number Sense Notes

Number Sense

Welcome to the chapter on Number Sense for Class 3. In this chapter, you will learn about numbers, how to read and write them, compare and order numbers, and use numbers in your daily life. By the end of this chapter, you will be able to work with numbers confidently and understand their importance!

Introduction

Numbers are everywhere! We use numbers to count, measure, compare, and solve problems. Understanding numbers helps us in school, at home, and in games.

Key Concepts

• Numbers: Symbols like 1, 2, 3, 4, 5, etc.
• Counting: Saying numbers in order to find out "how many".
• Comparing: Finding which number is bigger or smaller.
• Ordering: Arranging numbers from smallest to biggest or biggest to smallest.
• Place Value: The value of a digit depending on its place in a number.
• Odd and Even Numbers: Numbers that can or cannot be divided by 2.

1. Reading and Writing Numbers

Numbers can be written in figures (like 25) and in words (like twenty-five). Practice writing numbers from 1 to 100 in both figures and words.

2. Counting Objects

We count objects to know how many there are. For example, if you have 8 pencils, you count: 1, 2, 3, 4, 5, 6, 7, 8.

3. Comparing Numbers

• Greater than (>): 9 > 6 (9 is greater than 6)
• Less than (<): 4 < 7 (4 is less than 7)
• Equal to (=): 12 = 12 (both are equal)

4. Ordering Numbers

• Ascending order: Arranging numbers from smallest to biggest (e.g., 3, 7, 12, 18).
• Descending order: Arranging numbers from biggest to smallest (e.g., 20, 15, 9, 2).

5. Place Value

Each digit in a number has a place value.
In 56, the 5 is in the tens place (value 50), and the 6 is in the ones place (value 6).
In 274, the 2 is in the hundreds place (value 200), 7 in tens (70), and 4 in ones (4).

6. Odd and Even Numbers

• Even numbers: Numbers that can be divided by 2 (like 2, 4, 6, 8, 10).
• Odd numbers: Numbers that cannot be divided by 2 (like 1, 3, 5, 7, 9).

7. Numbers in Daily Life

• Tell the time
• Count money
• Measure length and weight
• Keep scores in games

Fun Activity: Number Hunt!

Look around your home or classroom. Write down all the numbers you see (on clocks, books, calendars, etc.). Try to read them aloud and write them in words.

Summary

• Numbers help us count, compare, and measure things.
• We use numbers every day in many ways.
• Place value helps us understand the value of each digit in a number.
• Numbers can be odd or even.

Practice Questions

Try these questions to test your understanding:

1. Write the numbers from 1 to 20 in words.
2. Which is greater: 18 or 13?
3. Arrange these numbers in ascending order: 12, 5, 19, 7.
4. What is the place value of 3 in 34?
5. Is 14 an odd or even number?

Challenge Yourself

• Count all the windows and doors in your house. Which is more?
• Write the numbers from 50 to 70 in figures and words.

Did You Know?

• Zero (0) means nothing or none.
• The largest two-digit number is 99, and the smallest three-digit number is 100.

Glossary

• Number: A symbol used for counting.
• Place Value: The value of a digit based on its position.
• Ascending Order: Smallest to biggest.
• Descending Order: Biggest to smallest.
• Odd Number: Not divisible by 2.
• Even Number: Divisible by 2.

Answers to Practice Questions

1. One, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen, twenty.
2. 18 is greater than 13.
3. 5, 7, 12, 19
4. 30 (tens place)
5. 14 is an even number.

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Remember, numbers are everywhere! Use them to count, compare, and have fun learning!