Given the sum 100=64+36 , rewrite 64+36 using their GCF and multiplication.

1(64+36)
4(16×9)
4(16+9)
2(32+18)

The greatest common factor (GCF) of 64 and 36 is 4. By factoring out the GCF, we can rewrite 64+36 as 4(16+9).