To do groups of 9, she could make 2 rows of 9. To do 3, she could do 6 rows of 3. Last, to do 6 she could do 3 rows of 6. :)
336
112x = 336
112
x3
=336
37.3
x3
= 112
37.3
x9
=336
This is the associative property, since any numbers can <em>associate </em>with each other, via the parentheses.
Plug in 500 for h in the equation and you get:
e=3 (500)
e=1500