1) 15 3/10 + 4 7/10 = 19 10/10 = 20
2) 2 2/7 + 5 4/21 = 2 6/7 + 5 4/21 = 2 126/147 + 5 28/147 = 7 154/147 = 8 7/147
3) 6 11/15 - 2 11/18 = 6 44/60 - 2 33/60 = 4 11/60
4) 12 - 5 9/10 = 12 - 5 18/20 = 12 - 5 9/10 = 6 1/10
1) 15 3/10 + 4 7/10 = 19 10/10 = 20
2) 2 2/7 + 5 4/21 = 2 6/7 + 5 4/21 = 2 126/147 + 5 28/147 = 7 154/147 = 8 7/147
3) 6 11/15 - 2 11/18 = 6 44/60 - 2 33/60 = 4 11/60
4) 12 - 5 9/10 = 12 - 5 18/20 = 12 - 5 9/10 = 6 1/10