The GCF of 18 and 48 is 6. The LCM of 18 and 48 is 144.
Factors of 18: 1, 2, 3, 6, 9, 18.
Factors of 48: 1, 2, 3, 4, 6, 8, 12, 16, 24, 48.
Common factors: 1, 2, 3 and 6. The greatest of these is 6.
18 = 2 × 3 × 3
48 = 2 × 2 × 2 × 2 × 3
GCF: multiply the prime factors both numbers share: 2 × 3 = 6.
LCM: multiply every prime the maximum number of times it appears in either number: 2 × 2 × 2 × 2 × 3 × 3 = 144.
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 6, so GCF(18, 48) = 6.
Multiples of 18: 18, 36, 54, 72, 90, 108, 126, 144, 162, ...
Multiples of 48: 48, 96, 144, 192, ...
The first number in both lists is 144.
6 × 144 = 864 = 18 × 48. This always holds for two numbers, so you can find the LCM as (18 × 48) ÷ 6 = 144.
Divide the top and bottom by the GCF 6: 18/48 = 3/8.
| Numbers | GCF | LCM |
|---|---|---|
| 2 and 18 | 2 | 18 |
| 3 and 18 | 3 | 18 |
| 4 and 18 | 2 | 36 |
| 5 and 18 | 1 | 90 |
| 6 and 18 | 6 | 18 |
| 7 and 18 | 1 | 126 |
| 2 and 48 | 2 | 48 |
| 3 and 48 | 3 | 48 |
| 4 and 48 | 4 | 48 |
| 5 and 48 | 1 | 240 |
| 6 and 48 | 6 | 48 |
| 7 and 48 | 1 | 336 |
See also: factors of 18 · factors of 48.
Different numbers? Use the GCF and LCM calculator (any amount of numbers) or browse all GCF and LCM pairs.