1 x 40, 2 x 20, 4 x 10, 5 x 8, 8 x 5, 10 x 4, 20 x 2, 40 x 1
1, 2 and 4.
The GCF is 20.
From the rules of divisibility, we know that 40 is divisible by 1, 2, 4 and 5. Divide those numbers into 40 to get the rest. (40,1)(20,2)(10,4)(8,5)
2
1600
200
80%
1,2,4,5,8,10,20,40 1,3,5,9,15,45
$20
8/40 is 0.2 or 20%
1 and 2
50% of 40 is 20.