2 x 3 x 3
1 x 1 x 18
1 x 2 x 9
1 x 3 x 6
and so on ...
15
Prime factorization of 99 = 3 * 3 * 11
3 x 3 x 3 x 5 = 135
3 x 5 x 5 = 75
1, 2, 3, 6, 9, 18: (1 x 18, 2 x 9, 3 x 6, 6 x 3, 9 x 2, 18 x 1)
How about: 3 times -6 = -18 as one example
15
-15
They are: 1*18 = 18, 2*9 = 18 and 3*6 = 18
3 x6 =18 2 x9 =18 1 x 18 =18
-69
You can multiply the number 18 by different numbers that are relatively prime, for example by different prime numbers.
63
Presumably, the theory is that it's easier to multiply by small numbers than larger ones. If there's a number that you need multiplied by 18, multiply it by 3, then multiply that total by 3, then multiply that total by 2.
63
135
21