The common factors are: 1, 3
1 and the highest common factor is 6
Since 18 is a factor of 36, all the factors of 18 will be common to 36. 1,2,3,6,9,18
6
Because 18 is a factor of 36. All of its factors, including itself, are common to 36.
Factors of 18: 1, 2, 3, 6, 9, 18Factors of 20: 1, 2, 4, 5, 10, 20
3
It is 9
It is: 126
The common factors of 30 and 40 are 1, 2, 5, 10
The common factors of 30 and 63 are 1 and 3.
The common factors of 30 and 21 are 1 and 3.