Answer & Step-by-step explanation:
8 is 2×2×2.
Doubling a number is the same as multiplying ×2.
So maybe you could take the 9 and double it, 18.
Double it again, 36.
Double it again, 72.
Or anyway that you can "take apart" 8 and 9 in smaller numbers and rearrange, because you can multiply in any order.
For example, if you don't know your 8 or 9 times tables, but you know your 3 and 4 and 6 times tables:
8 is 4×2 and
9 is 3×3.
8×9 is the same as 2×3 and 4×3
6×12
which is 72.
Hope this helps.
