Subtraction Chapter Notes | Mathematics Class 2 ICSE PDF Download

Introduction

Subtraction is like taking away some candies from a jar and seeing how many are left! In this exciting chapter, we will learn how to subtract numbers, find differences, and even solve fun problems. From taking away small numbers to working with bigger ones, we’ll explore easy ways to subtract and check our answers. Let’s dive into the world of subtraction and make math super fun!

Subtraction Facts

• Subtraction means taking a smaller number away from a bigger number to find the difference.
• The order matters: you cannot subtract a bigger number from a smaller one (e.g., 3 - 4 is not possible).

• Subtracting zero from any number gives the same number.

• Subtracting a number from itself always results in zero.

• Every addition fact has two subtraction facts.
• Every subtraction fact has two addition facts.

Subtracting 2-Digit Numbers (without borrowing)

• Subtract 2-digit numbers by breaking them into tens and ones.
• Step 1: Subtract the ones place digits first.
• Step 2: Subtract the tens place digits.
• Write the final answer by combining the results.

Subtraction by Borrowing

• When the digit to subtract is larger than the digit in the same place, borrow from the next place (tens).
• Step 1: Borrow 1 from the tens place, reducing it by 1, and add 10 to the ones place.
• Step 2: Subtract the ones place digits.
• Step 3: Subtract the tens place digits.
• Write the final difference.

Checking Subtraction

• To check if subtraction is correct, add the difference to the smaller number.
• The sum should equal the bigger number.

Finding the Missing Digits

• To find the smaller number, subtract the difference from the bigger number.
• To find the bigger number, add the smaller number to the difference.
• For missing digits in the bigger number, start with ones, then tens, then hundreds.

Word Problems

• Word problems involve subtraction to find the difference between quantities.
• Identify the total amount and the amount to subtract.
• Use subtraction to find the answer.
• Words like “take away,” “minus,” “decrease,” or “difference” indicate subtraction.

Example: During their summer vacations, 58 students went on a trip to Goa. There were 39 boys. How many girls were there?

• Total students: 58.
• Number of boys: 39.
• Write:

• Subtract: 58 - 39 = 19.
• Answer: There were 19 girls.

Mental Subtraction

• Mental subtraction uses shortcuts to subtract without writing.
• Method 1: Break the number to subtract into tens and ones, then subtract in parts.
• Method 2: Find what number to add to the smaller number to reach the bigger number (works when numbers are close).
• Method 3: Subtract an easy number close to the actual number, then adjust the answer.