2/3 + 1/9 =
1/2 + 2/5 =
1/3 + 1/7 =
5/10 + 1/2 =
1/2 - 1/8 =
7/9 - 4/9
12/15 - 1/5 =
5/8 - 1/5 =
2/3 x 1/9 =
1/4 x 1/2 =
3/8 x 2/5 =
7/4 x 2/3 =