The GCF of 8 and 10 is 2. The LCM of 8 and 10 is 40.
Factors of 8: 1, 2, 4, 8.
Factors of 10: 1, 2, 5, 10.
Common factors: 1 and 2. The greatest of these is 2.
8 = 2 × 2 × 2
10 = 2 × 5
GCF: multiply the prime factors both numbers share: 2 = 2.
LCM: multiply every prime the maximum number of times it appears in either number: 2 × 2 × 2 × 5 = 40.
Divide the larger number by the smaller and repeat with the remainder until it is 0. The last non-zero remainder is the GCF.
The last non-zero remainder is 2, so GCF(8, 10) = 2.
Multiples of 8: 8, 16, 24, 32, 40, 48, ...
Multiples of 10: 10, 20, 30, 40, 50, ...
The first number in both lists is 40.
2 × 40 = 80 = 8 × 10. This always holds for two numbers, so you can find the LCM as (8 × 10) ÷ 2 = 40.
Divide the top and bottom by the GCF 2: 8/10 = 4/5.
| Numbers | GCF | LCM |
|---|---|---|
| 2 and 8 | 2 | 8 |
| 3 and 8 | 1 | 24 |
| 4 and 8 | 4 | 8 |
| 5 and 8 | 1 | 40 |
| 6 and 8 | 2 | 24 |
| 7 and 8 | 1 | 56 |
| 2 and 10 | 2 | 10 |
| 3 and 10 | 1 | 30 |
| 4 and 10 | 2 | 20 |
| 5 and 10 | 5 | 10 |
| 6 and 10 | 2 | 30 |
| 7 and 10 | 1 | 70 |
See also: factors of 8 · factors of 10 · 8/10 as a decimal.
Different numbers? Use the GCF and LCM calculator (any amount of numbers) or browse all GCF and LCM pairs.