You want to put a 3 inch thick layer of topsoil for a new 13 ft by 31 ft garden. The dirt store sells by the cubic yards. How many cubic yards will you need to order

38+105= 143, 39+104=143, and you will find then adding the numbers on opposite sides, moving inwards yields the answer 138 every time. because of this, you’re going to multiply 138 times the number of pairs, which is 34. therefore, 34*138= 4692(i’m sorry if it’s the wrong numbers, but it’s the right concept)

The shelves will hold 270 books in total