Answer :
If you take 9x4 you get 36 and multiply that by 2 (it's 2 because 4x2 is 8) you get 72
If you take 9x8 you get 72
If you take 9x8 you get 72
It can help you explain 9x8 because 9x4 equals 36. 4 is the half of 8. So you would do 36 + 36 which equals the product of 9x8=72.