The factors of 30 are:
1, 2, 3, 5, 6, 10, 15, 30
The factors of 36 are:
1, 2, 3, 4, 6, 9, 12, 18, 36
Common factors of 28 and 30 are: 1 and 2.
1, 2, 3 and 6
All of them except 23 and 29 which are prime numbers having only two factors
120
1, 2, 4, 5, 10, 20 1, 2, 3, 5, 6, 10, 15, 30
The LCM is: 90
GCF = 3
The GCF is 15.
150
The GCF is 2
21,22,23,24,25,26,27,28,29
the gcf is 3