What is Subtraction?

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Grade Level:

Pre-School – Class 2

All domains without exception

Definition

What is it?

Subtraction is a basic math operation where you take away one number from another. It helps us find the difference between two quantities or how much is left after something is removed.

Simple Example

Quick Example

Imagine you have 5 delicious ladoos. If your friend eats 2 of them, how many ladoos are left for you? You can find this by subtracting 2 from 5.

Worked Example

Step-by-Step

Let's say a cricket team scored 185 runs in the first innings and 230 runs in the second innings. How many more runs did they score in the second innings?
1. We want to find the difference between 230 and 185.
2. Write the larger number (230) on top and the smaller number (185) below it, aligning the digits.
230
- 185
-----
3. Start subtracting from the ones place: 0 - 5. We can't do this, so we 'borrow' 1 ten from the tens place. The 3 becomes 2, and the 0 becomes 10. Now, 10 - 5 = 5.
2 10
2 3 0
- 1 8 5
-------
5
4. Move to the tens place: 2 - 8. Again, we can't do this, so we borrow 1 hundred from the hundreds place. The 2 becomes 1, and the 2 (from the tens place) becomes 12. Now, 12 - 8 = 4.
1 12
2 3 0
- 1 8 5
-------
4 5
5. Finally, in the hundreds place: 1 - 1 = 0.
1 12
2 3 0
- 1 8 5
-------
0 4 5
Answer: The team scored 45 more runs in the second innings.

Why It Matters

Subtraction is fundamental to understanding quantities and differences, which is crucial in almost all math concepts. It's used by shopkeepers to calculate change, by engineers to measure differences in designs, and by scientists to compare data.

Common Mistakes

MISTAKE: Always subtracting the smaller digit from the larger digit, even if it's in the top number. For example, in 32 - 18, doing 2-8 as 8-2=6. | CORRECTION: Always subtract the bottom digit from the top digit. If the top digit is smaller, you must 'borrow' from the next place value to the left.

MISTAKE: Forgetting to adjust the borrowed digit. If you borrow from the tens place (e.g., 3 becomes 2), sometimes students forget to use the '2' in the next step. | CORRECTION: After borrowing, immediately change the digit you borrowed from to one less than its original value to avoid errors.

MISTAKE: Not aligning numbers correctly by place value (ones under ones, tens under tens). This is especially common with numbers of different lengths, like 123 - 45. | CORRECTION: Always write numbers stacked vertically, making sure the ones digits are aligned, then tens, hundreds, and so on. Use zeros as placeholders if needed.

Practice Questions

Try It Yourself

QUESTION: You had 15 stickers. You gave 7 to your cousin. How many stickers do you have left? | ANSWER: 8 stickers

QUESTION: A bus started with 50 passengers. At the first stop, 12 passengers got off. How many passengers are still on the bus? | ANSWER: 38 passengers

QUESTION: A mobile phone costs Rs 12,500. If you have Rs 8,750 saved, how much more money do you need to buy the phone? | ANSWER: Rs 3,750

MCQ

Quick Quiz

What is the result of 98 - 45?

143

The Correct Answer Is:

Subtracting 5 from 8 in the ones place gives 3. Subtracting 4 from 9 in the tens place gives 5. So, 98 - 45 = 53.

Real World Connection

In the Real World

Every time you check your mobile data balance and see how much is left from your daily limit, you are doing subtraction. When a shopkeeper gives you change after you pay for groceries, they are using subtraction to figure out the correct amount.

Key Vocabulary

Key Terms

SUBTRACTION: The act of taking one number away from another | DIFFERENCE: The result of a subtraction problem | MINUEND: The number from which another number is subtracted (the larger number usually) | SUBTRAHEND: The number that is being subtracted (the smaller number usually) | BORROWING: A technique used in subtraction when a digit in the minuend is smaller than the corresponding digit in the subtrahend.

What's Next

What to Learn Next

Now that you understand basic subtraction, you can explore subtraction with larger numbers, decimal numbers, and even negative numbers. This will help you solve more complex problems in algebra and geometry!