The GCF of 2 and 20 is 2. The LCM of 2 and 20 is 20.
Factors of 2: 1, 2.
Factors of 20: 1, 2, 4, 5, 10, 20.
Common factors: 1 and 2. The greatest of these is 2.
2 = 2 (prime)
20 = 2 × 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 × 5 = 20.
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(2, 20) = 2.
Multiples of 2: 2, 4, 6, 8, 10, 12, 14, 16, 18, ...
Multiples of 20: 20, 40, ...
The first number in both lists is 20.
2 × 20 = 40 = 2 × 20. This always holds for two numbers, so you can find the LCM as (2 × 20) ÷ 2 = 20.
Divide the top and bottom by the GCF 2: 2/20 = 1/10.
| Numbers | GCF | LCM |
|---|---|---|
| 2 and 3 | 1 | 6 |
| 2 and 4 | 2 | 4 |
| 2 and 5 | 1 | 10 |
| 2 and 6 | 2 | 6 |
| 2 and 7 | 1 | 14 |
| 2 and 8 | 2 | 8 |
| 3 and 20 | 1 | 60 |
| 4 and 20 | 4 | 20 |
| 5 and 20 | 5 | 20 |
| 6 and 20 | 2 | 60 |
| 7 and 20 | 1 | 140 |
| 8 and 20 | 4 | 40 |
See also: factors of 2 · factors of 20 · 2/20 as a decimal.
Different numbers? Use the GCF and LCM calculator (any amount of numbers) or browse all GCF and LCM pairs.