You build and sell toy boxes. so far, you have built 15 toy boxes that you will sell for $60 each. how much money will you have if you build 20 more toy boxes and sell all of them?

15 plus 20 equals 35
35 times 60 equals 2100
they will make you $2100

Since you already have 15 boxes, and you want to build 20 more, you add the two numbers. 15+20=35.  Then, you multiply 35 by 60 since you are selling each for $60. 35x60=2100. So you will have $2100 dollars if you sell 35 boxes.