Question

Find the GCF 1. 12,21,30 2. 11,44

Answer 1

The GCF of 12, 21, and 30 is 3.
The factors of 12 are: 1, 2, 3, 4, 6, 12
The factors of 21 are: 1, 3, 7, 21
The factors of 30 are: 1, 2, 3, 5, 6, 10, 15, 30
Then the greatest common factor is 3.

The GCF of 11, and 44 is 11. 
The factors of 11 are: 1, 11
The factors of 44 are: 1, 2, 4, 11, 44
Then the greatest common factor is 11. 

Hope this helps.

Answer 2

1. 420 (30*14=420) (21*20=420) (12*35=420)
2. 44 (11*4=44) (44*1=44)