Subtracting Like Fractions (Grade 3)
Subtracting like fractions follows the same simple rule as adding them. Since like fractions have the same denominator, you only need to subtract the numerators and keep the denominator unchanged.
In Class 3, subtraction of like fractions helps you find how much is left after using or eating part of something. For example, if a pizza has 5/8 remaining and you eat 2/8, you can subtract: 5/8 − 2/8 = 3/8.
What is Subtracting Like Fractions - Class 3 Maths (Fractions (Grade 3))?
To subtract like fractions (fractions with the same denominator):
a/d − b/d = (a − b)/d
Subtract the numerators. Keep the denominator the same.
Example: 5/7 − 2/7 = (5 − 2)/7 = 3/7
The denominator stays as 7 because the size of each part has not changed — only the number of parts has decreased.
Types and Properties
Types of Like Fraction Subtraction
1. Simple Subtraction
The result is a smaller proper fraction.
- 4/5 − 1/5 = 3/5
- 7/10 − 3/10 = 4/10
2. Subtracting to Get Zero
When both fractions are the same, the result is 0.
- 3/4 − 3/4 = 0/4 = 0
3. Subtracting from a Whole
A whole can be written as a fraction (e.g., 1 = 4/4), and then you subtract.
- 4/4 − 1/4 = 3/4
- 6/6 − 2/6 = 4/6
Solved Examples
Example 1: Example 1: Basic Subtraction
Question: Find 5/8 − 2/8.
Think:
- Same denominator (8)
- 5 − 2 = 3
- Answer = 3/8
Answer: 5/8 − 2/8 = 3/8
Example 2: Example 2: Subtracting to Get Zero
Question: Find 4/6 − 4/6.
Think:
- 4 − 4 = 0
- Answer = 0/6 = 0
Answer: 4/6 − 4/6 = 0
Example 3: Example 3: Subtracting from a Whole
Question: A cake is whole (5/5). Meera eats 2/5. What fraction is left?
Think:
- Whole = 5/5
- 5/5 − 2/5 = 3/5
Answer: 3/5 of the cake is left.
Example 4: Example 4: Word Problem – Ribbon
Question: Ria has 7/10 of a ribbon. She uses 3/10 for a gift. What fraction of the ribbon is left?
Think:
- 7/10 − 3/10 = 4/10
Answer: 4/10 of the ribbon is left.
Example 5: Example 5: Larger Denominator
Question: Find 9/12 − 5/12.
Think:
- Same denominator (12)
- 9 − 5 = 4
- Answer = 4/12
Answer: 9/12 − 5/12 = 4/12
Example 6: Example 6: Word Problem – Pizza
Question: A pizza is cut into 8 equal slices. Dev eats 3/8 of the pizza. Arjun eats 2/8. What fraction is left?
Think:
- Total eaten = 3/8 + 2/8 = 5/8
- Pizza left = 8/8 − 5/8 = 3/8
Answer: 3/8 of the pizza is left.
Example 7: Example 7: Visual Problem
Question: A rectangle is divided into 6 equal parts. 5 parts are shaded. If 2 parts are unshaded, what fraction remains shaded?
Think:
- Shaded parts = 5
- Unshaded = 2 → so we remove 2 from the shaded
- 5/6 − 2/6 = 3/6
Answer: 3/6 remains shaded.
Example 8: Example 8: Finding the Missing Fraction
Question: 7/9 − ?/9 = 4/9. Find the missing fraction.
Think:
- 7 − ? = 4
- ? = 7 − 4 = 3
- Missing fraction = 3/9
Answer: The missing fraction is 3/9.
Example 9: Example 9: Word Problem – Water
Question: A bottle is 6/8 full. Priya drinks 1/8. How full is the bottle now?
Think:
- 6/8 − 1/8 = 5/8
Answer: The bottle is 5/8 full.
Example 10: Example 10: Subtracting Zero
Question: Find 4/5 − 0/5.
Think:
- 4 − 0 = 4
- Answer = 4/5
Answer: 4/5 − 0/5 = 4/5 (subtracting zero gives the same fraction).
Real-World Applications
Where Do We Subtract Like Fractions?
- Food: Finding how much pizza, cake, or pie is left after eating some slices.
- Measuring: Finding remaining length of ribbon, rope, or cloth after cutting.
- Water: Calculating how much water remains in a glass or bottle after drinking.
- Colouring: Finding how much of a shape is not yet coloured.
Key Points to Remember
- Like fractions have the same denominator.
- To subtract: subtract the numerators, keep the denominator.
- The answer cannot be negative at this level (always subtract smaller from larger).
- Subtracting a fraction from itself gives 0.
- Subtracting 0 from a fraction gives the same fraction.
- A whole can be written as a fraction (e.g., 1 = 8/8) before subtracting.
Practice Problems
- Find 6/7 − 2/7.
- Find 8/10 − 5/10.
- Find 4/4 − 1/4.
- Aditi has 5/6 of a chocolate bar. She eats 3/6. What fraction is left?
- Find 11/12 − 7/12.
- A jug is full (8/8). Kavi pours out 3/8. What fraction remains?
- Find the missing number: 9/10 − ?/10 = 4/10.
- Aman colours 7/9 of a circle and then erases 2/9. What fraction is still coloured?
Frequently Asked Questions
Q1. How do you subtract like fractions?
Subtract the numerators (top numbers) and keep the denominator (bottom number) the same. For example, 6/8 − 2/8 = 4/8.
Q2. What are like fractions?
Like fractions are fractions with the same denominator. Examples: 3/7 and 5/7, or 2/10 and 8/10.
Q3. Why does the denominator stay the same?
The denominator tells the size of each part. Subtraction only changes how many parts you have, not the size of each part. So the denominator stays the same.
Q4. Can the answer be zero?
Yes. If both fractions are equal, the answer is 0. For example, 3/5 − 3/5 = 0/5 = 0.
Q5. How do I subtract a fraction from 1?
Write 1 as a fraction with the same denominator. For example, 1 − 2/5 → write 1 as 5/5 → 5/5 − 2/5 = 3/5.
Q6. Can I subtract fractions with different denominators?
Not directly with this method. You first need to find a common denominator. This is taught in higher classes.
Q7. What is the difference between adding and subtracting like fractions?
The process is the same — keep the denominator. For addition, add the numerators. For subtraction, subtract the numerators.
Q8. Can the numerator be larger than the denominator in the answer?
In subtraction, no — since you are taking away, the answer is always less than or equal to what you started with.
Q9. How do I check my answer?
Add the answer to the fraction you subtracted. If you get back the original fraction, your answer is correct. For example, 7/9 − 3/9 = 4/9. Check: 4/9 + 3/9 = 7/9.
