1 and 2.
2
Six
The first four common multiples of 4 and 7 are 28, 56, 84, and 102
20 has six factors.
Four, four, six, three, six and two factors respectively.
The common factors of six and eight are: 1, 2
Twelve, four and six factors, respectively.
It is six.
4
The greatest common factor is six.
There are only 2 common factors; 1 and 2. You likely mean what are the first 6 common multiples, for which the first six multiples of 8 are the answer. 8,16,24,32,40 and 48.
1 and 2