Ok they are trying to explain that you can solve this problem “easily” in their mind by making the second amount an even foot amount.
So this problem would be:
4 ft. 1 in. 4 ft. 3 in.
- 1 ft. 10 in. Add 2 in to make 2 ft. - 2 ft.
So the answer is. 2ft. 3in.
