3 1/2- 2 1/4
3 1/2 - 2 1/4 = 1 1/4
3 + 1/2 = 7/2 and
2 + 1/4 = 9/4
7/2 - 9/4 =
14/4 - 9/4 =
5/4 =
1 + 1/4
its called a caculater use it
