Given the sum 99=33+66 , rewrite 33+66 using their GCF and multiplication.

The GCF (Greatest Common Factor) of 33 and 66 is 33.

Therefore, we can rewrite 33 + 66 as:

33 × 1 + 33 × 2

Multiplying both terms by 33, we get:

33(1 + 2)

= 33 × 3

= 99

So, 33 + 66 = 99 when written using their GCF and multiplication.