Like Denominators
1/2 + 1/2 =
2/2 or 1
1/4 + 2/6
2/9 + 3/10 =
47/90
1/1 + 1/6 =
7/6 or 1 1/6
2/4 + 3/9 =
5/6
12/20 + 10/15 =
19/15 or 1 4/15
8/20 + 3/15 =
3/5
6/12 + 4/12 =
5/6
11/20 - 5/12 =
2/15
8/12 + 1/20 =
43/60
20/40 + 30/60 =
240/240 or 1