Hello there!
This is the volume for a rectangular prism: V = whl
So now, we put in the numbers: V = whl = 4 · 8 · 4 = 128
Now, since it says that we need to find the volume of the crackers, we divide 128 with 4 (because the box is 1/4 full, so we use 4): 128 ÷ 4 = 32
So, 32 is your answer.
Hope I helped!