Andy is buying carpet squares for his living room. the length of the room is 20 feet, and the width is 16 feet. each carpet square covers 4 square feet. how many carpet squares will andy need to purchase to cover the room

For this case, the first thing you should do is find the area of the room. We can assume that the room is a rectangle, then the area will be:
 A = (w) * (l)
 Where,
 w: width
 l: long
 Substituting the values we have:
 A = (16) * (20)
 A = 320 feet ^ 2
 We note that each carpet covers only 4 feet ^ 2.
 Therefore the number of carpets will be:
 N = (320) / (4)
 N = 80
 Answer: 
 andy will need to buy 20 carpet squares to cover the room