In this task you will be given a list of lists, of numbers. For every inner list, you should multiply every number in that list and put the results in your answer. The output should be a list of numbers with the same length as the number of the lists in the input list.
[[-4, -18], [32, 45, 18, 42], [13, 6, -8, 33, -31], [38, 21, -4, -20, 1]]