100 x 400 would equal 40,000 because you would combine the zero's when multiplying.
Now you need to divide that number being 40,000 by 40
Dividing this would be changing to 1,000 because the two 4's would cancel each other out since they are both the leading number in their respective sides of the equation.
Therefore, 100 x 400 divided by 40 = 1,000
:) good luck in your future work.
