Let’s solve each subtraction problem step by step. Remember, to subtract unlike fractions (fractions with different denominators), we need to find a common denominator first — usually the least common multiple (LCM) of the two denominators. Then we rewrite both fractions with that common denominator and subtract the numerators.
We’ll go one by one:
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1. 2/5 - 1/10
- LCM of 5 and 10 is 10.
- Convert 2/5 → 4/10
- Now: 4/10 - 1/10 =
3/10
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2. 7/10 - 1/4
- LCM of 10 and 4 is 20.
- 7/10 = 14/20; 1/4 = 5/20
- 14/20 - 5/20 =
9/20
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3. 2/5 - 1/4
- LCM of 5 and 4 is 20.
- 2/5 = 8/20; 1/4 = 5/20
- 8/20 - 5/20 =
3/20
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4. 9/10 - 2/3
- LCM of 10 and 3 is 30.
- 9/10 = 27/30; 2/3 = 20/30
- 27/30 - 20/30 =
7/30
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5. 2/3 - 1/2
- LCM of 3 and 2 is 6.
- 2/3 = 4/6; 1/2 = 3/6
- 4/6 - 3/6 =
1/6
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6. 1/2 - 1/3
- LCM of 2 and 3 is 6.
- 1/2 = 3/6; 1/3 = 2/6
- 3/6 - 2/6 =
1/6
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7. 3/4 - 4/10
- Simplify 4/10 → 2/5 (optional, but helps)
- LCM of 4 and 5 is 20.
- 3/4 = 15/20; 2/5 = 8/20
- 15/20 - 8/20 =
7/20
*(Alternatively, use 4 and 10 → LCM=20: 3/4=15/20, 4/10=8/20 → same result)*
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8. 3/4 - 3/5
- LCM of 4 and 5 is 20.
- 3/4 = 15/20; 3/5 = 12/20
- 15/20 - 12/20 =
3/20
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Now the right column:
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9. 1/2 - 1/3
- Already did this above →
1/6
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10. 4/5 - 1/2
- LCM of 5 and 2 is 10.
- 4/5 = 8/10; 1/2 = 5/10
- 8/10 - 5/10 =
3/10
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11. 1/2 - 1/3
- Again →
1/6
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12. 6/10 - 1/2
- Simplify 6/10 → 3/5, or convert 1/2 to 5/10
- 6/10 - 5/10 =
1/10
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13. 2/3 - 2/10
- Simplify 2/10 → 1/5
- LCM of 3 and 5 is 15.
- 2/3 = 10/15; 1/5 = 3/15
- 10/15 - 3/15 =
7/15
*(Or use 3 and 10 → LCM=30: 2/3=20/30, 2/10=6/30 → 14/30 = 7/15 — same answer)*
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14. 4/10 - 1/4
- Simplify 4/10 → 2/5
- LCM of 5 and 4 is 20.
- 2/5 = 8/20; 1/4 = 5/20
- 8/20 - 5/20 =
3/20
*(Or use 10 and 4 → LCM=20: 4/10=8/20, 1/4=5/20 → same)*
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15. 1/3 - 3/10
- LCM of 3 and 10 is 30.
- 1/3 = 10/30; 3/10 = 9/30
- 10/30 - 9/30 =
1/30
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16. 4/5 - 2/3
- LCM of 5 and 3 is 15.
- 4/5 = 12/15; 2/3 = 10/15
- 12/15 - 10/15 =
2/15
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✔ All answers checked carefully.
Final Answer:
Left Column:
1. 3/10
2. 9/20
3. 3/20
4. 7/30
5. 1/6
6. 1/6
7. 7/20
8. 3/20
Right Column:
9. 1/6
10. 3/10
11. 1/6
12. 1/10
13. 7/15
14. 3/20
15. 1/30
16. 2/15
Parent Tip: Review the logic above to help your child master the concept of add and subtract fractions with unlike denominators worksheet.
