Let’s solve each part step by step.
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Part 1: List the factors for each number.
Factors are numbers that divide evenly into a given number (with no remainder).
1.
55:
Think: What multiplies to make 55?
→ 1 × 55 = 55
→ 5 × 11 = 55
So factors:
1, 5, 11, 55
2.
3:
Only divisible by 1 and itself →
1, 3
3.
24:
1×24, 2×12, 3×8, 4×6 →
1, 2, 3, 4, 6, 8, 12, 24
4.
94:
Even number → divisible by 2 → 94 ÷ 2 = 47
47 is prime → so factors:
1, 2, 47, 94
5.
45:
1×45, 3×15, 5×9 →
1, 3, 5, 9, 15, 45
6.
1:
Only factor is itself →
1
7.
6:
1×6, 2×3 →
1, 2, 3, 6
8.
7:
Prime number →
1, 7
9.
78:
Even → 78 ÷ 2 = 39
39 = 3×13 → so factors: 1, 2, 3, 6, 13, 26, 39, 78
Let’s check:
1×78, 2×39, 3×26, 6×13 → yes →
1, 2, 3, 6, 13, 26, 39, 78
10.
4:
1×4, 2×2 →
1, 2, 4
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Part 2: Find the greatest common factor (GCF) for each set of numbers.
GCF = largest number that divides both numbers evenly.
11.
15 and 35
Factors of 15: 1, 3, 5, 15
Factors of 35: 1, 5, 7, 35
Common: 1, 5 → GCF =
5
12.
50 and 35
50: 1, 2, 5, 10, 25, 50
35: 1, 5, 7, 35
Common: 1, 5 → GCF =
5
13.
93 and 48
93: 1, 3, 31, 93
48: 1, 2, 3, 4, 6, 8, 12, 16, 24, 48
Common: 1, 3 → GCF =
3
14.
44 and 33
44: 1, 2, 4, 11, 22, 44
33: 1, 3, 11, 33
Common: 1, 11 → GCF =
11
15.
46 and 74
46: 1, 2, 23, 46
74: 1, 2, 37, 74
Common: 1, 2 → GCF =
2
16.
70 and 90
70: 1, 2, 5, 7, 10, 14, 35, 70
90: 1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90
Common: 1, 2, 5, 10 → GCF =
10
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Part 3: Find the lowest common multiple (LCM).
LCM = smallest number that both numbers divide into evenly.
17.
8 and 7
Multiples of 8: 8, 16, 24, 32, 40, 48, 56...
Multiples of 7: 7, 14, 21, 28, 35, 42, 49, 56...
First common:
56
Or since 8 and 7 have no common factors (other than 1), LCM = 8 × 7 =
56
18.
9 and 10
No common factors except 1 → LCM = 9 × 10 =
90
Check:
Multiples of 9: 9, 18, 27, 36, 45, 54, 63, 72, 81, 90...
Multiples of 10: 10, 20, 30, 40, 50, 60, 70, 80, 90...
Yes →
90
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Final Answer:
1. 1, 5, 11, 55
2. 1, 3
3. 1, 2, 3, 4, 6, 8, 12, 24
4. 1, 2, 47, 94
5. 1, 3, 5, 9, 15, 45
6. 1
7. 1, 2, 3, 6
8. 1, 7
9. 1, 2, 3, 6, 13, 26, 39, 78
10. 1, 2, 4
11. 5
12. 5
13. 3
14. 11
15. 2
16. 10
17. 56
18. 90
Parent Tip: Review the logic above to help your child master the concept of math grade 7 worksheet.
