5 packs of gum contain 5*3=<<5*3=15>>15 sticks of gum.
If each brown box contains 4 cartons, 8 brown boxes contain 8 * 4= <<8*4=32>>32 cartons.
So, 8 brown boxes contain 32 * 15=<<32*15=480>>480 sticks of gum.
#### 480