Melanie packs boxes of envelope into a larger box. the volume of each box of envelopes is 1,200 cubic centimeters. which is the best estimate for the volume of the large box?

To answer this question, we use the concept of volume addition. If each of the n envelope is 1,200 cm³ then, the best estimate for the volume of the large box is 1200n where n is the number of boxes. This is similarly saying that we add up all the volumes of the each box.