Let’s solve each problem step by step. We’re adding or subtracting fractions with
unlike denominators, so we need to find a common denominator first.
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1. 2/3 + 1/2
Find LCD of 3 and 2 → 6
Convert:
2/3 = 4/6
1/2 = 3/6
Add: 4/6 + 3/6 = 7/6 → can write as 1 1/6, but since the box is empty, leave as improper fraction unless told otherwise. But let’s check if simplifying is needed — 7/6 is already simplified.
✔ Answer:
7/6
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2. 2/5 + 1/10
LCD of 5 and 10 → 10
2/5 = 4/10
1/10 stays
Add: 4/10 + 1/10 = 5/10 → simplify to 1/2
✔ Answer:
1/2
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3. 1/5 + 2/4
First, simplify 2/4 → 1/2 (optional, but easier)
Now: 1/5 + 1/2
LCD of 5 and 2 → 10
1/5 = 2/10
1/2 = 5/10
Add: 2/10 + 5/10 = 7/10
✔ Answer:
7/10
*(Alternatively, without simplifying first: 1/5 + 2/4 → LCD 20 → 4/20 + 10/20 = 14/20 = 7/10 — same result)*
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4. 3/5 + 3/8
LCD of 5 and 8 → 40
3/5 = 24/40
3/8 = 15/40
Add: 24/40 + 15/40 = 39/40 → already simplified
✔ Answer:
39/40
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5. 2/7 + 1/4
LCD of 7 and 4 → 28
2/7 = 8/28
1/4 = 7/28
Add: 8/28 + 7/28 = 15/28 → already simplified
✔ Answer:
15/28
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6. 3/5 - 3/10
LCD of 5 and 10 → 10
3/5 = 6/10
3/10 stays
Subtract: 6/10 - 3/10 = 3/10
✔ Answer:
3/10
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7. 4/6 - 1/12
Simplify 4/6 → 2/3 (optional)
But let’s use LCD of 6 and 12 → 12
4/6 = 8/12
1/12 stays
Subtract: 8/12 - 1/12 = 7/12
✔ Answer:
7/12
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8. 4/6 - 1/2
Simplify 4/6 → 2/3
Now: 2/3 - 1/2
LCD of 3 and 2 → 6
2/3 = 4/6
1/2 = 3/6
Subtract: 4/6 - 3/6 = 1/6
✔ Answer:
1/6
*(Without simplifying: 4/6 - 1/2 → LCD 6 → 4/6 - 3/6 = 1/6 — same)*
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9. 3/4 - 1/3
LCD of 4 and 3 → 12
3/4 = 9/12
1/3 = 4/12
Subtract: 9/12 - 4/12 = 5/12
✔ Answer:
5/12
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10. 7/8 - 3/4
LCD of 8 and 4 → 8
7/8 stays
3/4 = 6/8
Subtract: 7/8 - 6/8 = 1/8
✔ Answer:
1/8
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Final Answer:
1. 7/6
2. 1/2
3. 7/10
4. 39/40
5. 15/28
6. 3/10
7. 7/12
8. 1/6
9. 5/12
10. 1/8
Parent Tip: Review the logic above to help your child master the concept of adding and subtracting fractions with like denominators worksheet 4th grade.
