32 and 48
The GCF is 1.
40 and 72
72 and 40
GCF of numbers 96 128 and 160 is 32.
You need at least two numbers to find a GCF. If that's 32, 40 and 28, the GCF is 4.
gcf (greatest common factor) is usually calculated for two (or more) numbers, not for a single number.
32 and 64
Here's a good method to quickly find GCFs: (1) Replace the larger number with the difference of the two numbers. (2) If the two new numbers are the same, then that gives the GCF. Otherwise repeat step (1) on the new numbers. With 64 and 32: (64,32) -> (32,32) (64 has been replaced with 32 since 64-32=32) The two numbers are now the same, so the answer is 32.
The GCF of 16 and 32 is 16.
You need at least two numbers to find a GCF.