Introduction

Number sense is the understanding of numbers, their relationships, and how they are used in calculations. It helps in solving mathematical problems effectively.

Place Value and Face Value

Each digit in a number has a place value and a face value:

• Place Value: The value of a digit based on its position in a number.
• Face Value: The actual value of the digit itself.

Types of Numbers

Natural and Whole Numbers

• Natural Numbers: Counting numbers starting from 1 (1, 2, 3, 4, ...).
• Whole Numbers: Natural numbers including zero (0, 1, 2, 3, ...).

Even and Odd Numbers

• Even Numbers: Numbers divisible by 2 (2, 4, 6, 8, ...).
• Odd Numbers: Numbers not divisible by 2 (1, 3, 5, 7, ...).

Prime and Composite Numbers

• Prime Numbers: Numbers with only two factors (1 and itself), e.g., 2, 3, 5, 7.
• Composite Numbers: Numbers with more than two factors, e.g., 4, 6, 8, 9.

Basic Arithmetic Operations

Addition and Subtraction

Used to find the total or difference between numbers.

Multiplication and Division

Multiplication is repeated addition, while division splits a number into equal parts.

Comparison of Numbers

Numbers can be compared using the symbols:

• > (greater than)
• < (less than)
• = (equal to)

Rounding Off Numbers

Numbers can be rounded to the nearest tens, hundreds, or thousands for easy calculations.

Application of Number Sense

• Understanding prices and expenses.
• Managing money and savings.
• Solving real-life mathematical problems.

Conclusion

Number sense is a fundamental concept in mathematics that helps in understanding and working with numbers efficiently.