The GCF is 6.
To find the GCF of two (or more) numbers, factor them , and see which numbers are common to both strings of numbers, and reduce the 'string' to '1'. Hence 2)42 3)21 7)7 = 1 & 2)72 2)36 2)18 3)9 3)3 = 1 Hence one lot of '2' is common to both numbers. Similarly one lot of '3' is common to both numbers. Hence 2 x 3 = 6 is the GCF of '42' & '72'. NB THe other 2's and the '3' and '7' are NOT common factors as they do NOT appear in both strings of numbers.
The GCF is 18.
The GCF is 9.
The GCF is 8.
The GCF is 8.
The GCF is 9.
It is 3
The GCF is 8.
The GCF is 8.
The GCF is 4.
The GCF is 1.
The GCF is 12.