3 3/4 + 1 1/2 = 3 3/4 + 1 2/4 = 4 5/4 = 5 1/4
2 5/6 - 1 5/12 = 2 10/12 - 1 5/12 = 1 5/12
4 - 1 2/3 = 3 3/3 - 1 2/3 = 2 1/3
3 2/7 - 6/7 = 2 9/7 - 6/7 = 2 3/7
1 1/3 * 4 = 4/3 * 4 = 16/3 = 5 1/3
3 1/4 * 2/5 = 13/4 * 2/5 = 26/20 = 1 6/20 = 1 3/10
2 1/4 : 3 = 9/4 : 3 = 9/4 * 1/3 = (3*1)/(4*1) = 3/4
20 : 2 1/2 = 20 : 5/2 = 20 * 2/5 = (4*2)/1 = 8