Subtracting Decimals (Grade 4)
Subtracting decimals follows the same principle as adding decimals: line up the decimal points, then subtract column by column from right to left. Borrowing works exactly as it does with whole numbers.
Decimal subtraction is used when calculating change after shopping (₹100.00 − ₹67.50), finding the difference in measurements (5.8 m − 3.25 m), or comparing weights.
What is Subtracting Decimals - Class 4 Maths (Decimals)?
Steps to subtract decimals:
- Write the numbers vertically with decimal points aligned.
- Add trailing zeros so both numbers have the same number of decimal places.
- Subtract column by column from right to left.
- Borrow from the next column when needed (just like whole numbers).
- Place the decimal point in the answer directly below.
Align decimals → Add zeros → Subtract → Borrow if needed → Place decimal
Solved Examples
Example 1: Example 1: Simple Subtraction of Tenths
Problem: Find 7.8 − 3.5.
Solution:
7.8
− 3.5
-----
4.3
Answer: 4.3
Example 2: Example 2: Subtraction with Borrowing
Problem: Find 6.3 − 2.7.
Solution:
Step 1: 3 tenths − 7 tenths: cannot do. Borrow 1 one (= 10 tenths).
13 tenths − 7 tenths = 6 tenths. 5 ones − 2 ones = 3 ones.
6.3
− 2.7
-----
3.6
Answer: 3.6
Example 3: Example 3: Subtracting Hundredths
Problem: Find 9.56 − 4.23.
Solution:
9.56
− 4.23
------
5.33
Answer: 5.33
Example 4: Example 4: Different Decimal Places
Problem: Find 8.4 − 3.15.
Solution:
Step 1: Write 8.4 as 8.40.
8.40
− 3.15
------
5.25
Answer: 5.25
Example 5: Example 5: Subtracting from a Whole Number
Problem: Find 10 − 4.35.
Solution:
Step 1: Write 10 as 10.00.
10.00
− 4.35
------
5.65
Answer: 5.65
Example 6: Example 6: Word Problem — Change
Problem: Dev paid ₹100 for a book costing ₹72.50. How much change did he get?
Solution:
100.00
− 72.50
-------
27.50
Answer: Dev got ₹27.50 change.
Example 7: Example 7: Word Problem — Length
Problem: A bamboo pole is 6.5 m long. Ria cuts off 2.75 m. How long is the remaining piece?
Solution:
6.50
− 2.75
------
3.75
Answer: The remaining piece is 3.75 m.
Example 8: Example 8: Word Problem — Weight
Problem: A bag of flour weighs 5.2 kg. After using some, it weighs 3.45 kg. How much flour was used?
Solution:
5.20
− 3.45
------
1.75
Answer: 1.75 kg of flour was used.
Example 9: Example 9: Finding the Missing Number
Problem: _____ − 2.6 = 4.9. Find the missing number.
Solution:
Step 1: Add 2.6 to both sides: Missing number = 4.9 + 2.6 = 7.5
Answer: 7.5
Key Points to Remember
- Always align the decimal points before subtracting.
- Add trailing zeros to make both numbers have equal decimal places.
- Subtract from right to left, borrowing when the top digit is smaller.
- When subtracting a decimal from a whole number, write the whole number with .00.
- The decimal point in the answer goes directly below the other decimal points.
- To check your answer: answer + subtracted number should equal the original number.
Practice Problems
- Find 8.6 − 3.4.
- Find 12.45 − 7.28.
- Find 9 − 3.67.
- Meera had ₹50. She spent ₹23.75 on a tiffin box. How much is left?
- A jug holds 3.5 litres. After pouring out 1.85 litres, how much water remains?
- Find 15.3 − 8.47.
- _____ − 5.8 = 3.2. Find the missing number.
Frequently Asked Questions
Q1. How do you subtract two decimal numbers?
Align the decimal points, add trailing zeros if needed, subtract from right to left borrowing when necessary, and place the decimal point in the answer below the others.
Q2. What if the top digit is smaller than the bottom digit?
Borrow 1 from the next column to the left, just as you do in whole number subtraction. For example, to compute 5.3 - 2.7: borrow from 5, making it 4, and the 3 becomes 13 tenths.
Q3. How do you subtract a decimal from a whole number?
Write the whole number with a decimal point and zeros. For example, 8 becomes 8.00. Then subtract normally.
Q4. How do you check decimal subtraction?
Add the answer to the number you subtracted. If it equals the original number, the subtraction is correct. For example, 7.5 - 2.3 = 5.2; check: 5.2 + 2.3 = 7.5.
Q5. Does adding zeros change the value of a decimal?
No. Adding zeros after the last decimal digit does not change the value. 3.5, 3.50, and 3.500 all represent the same number.
Q6. Where is decimal subtraction used in real life?
It is used when calculating change, finding differences in measurements (height, weight, distance), and in billing and accounting.
Q7. Can you subtract a larger decimal from a smaller one?
In Class 4, you always subtract the smaller from the larger. Subtracting a larger from a smaller gives a negative number, which is covered in higher classes.
Q8. Is subtracting decimals in the NCERT Class 4 syllabus?
Yes, subtraction of decimals (up to two decimal places) is part of the CBSE/NCERT Class 4 curriculum under the Decimals chapter.
