2/1 : 4/3
(-6/4 +-2/4) x -1
8/4
7/6
3/4 x 1/3
6/20 + 21/20
9/5
1/2 x (3 +3/5)
3/2
10/2 - 6/2
3/12
27/20
4/2
2/3 + 3/6
