A rectangular 12x20 waffle is divided into 1x1 squares. An ant crawls along a straight path from one corner to the opposite corner. How many squares of the waffle does the ant cross through?

Lay out a rectangle with a width of 5 and a height of 3

As shown here : https://www.desmos.com/calculator/qnelrpyogs

The ant will cross 7 distinct squares

So....in a rectangle with a width of 20 and a height of 12......the ant will cross 4 times as many squares = 28