Theo builds the first layer of a rectangular prism using 4 unit cubes. he adds 3 more layers of 4 unit cubes each. how many unit cubes does he use for the prism?
First you multiply 3 and 4 to get 12, then add 4 to get 16. There is also another way to do it you can draw a picture of 4 blocks then add 3 more of the 4 blocks then add one more of the 4 blocks to get 16. 16 is the answer! Hope this helped ( :