1) 19/60 - 3/20 = 1/20 2) 17/120 - 1/90 = 1/120 3) 9/10 - (3/4 - 3/5) + 5/8 = 9/10 - (15/20 - 12/20) + 5/8 = 9/10 - 3/20 + 5/8 = 36/40 - 6/40 + 25/40 = 55/40 = 11/8
1) 19/60 - 3/20 = 1/20
2) 17/120 - 1/90 = 1/120
3) 9/10 - (3/4 - 3/5) + 5/8
= 9/10 - (15/20 - 12/20) + 5/8
= 9/10 - 3/20 + 5/8
= 36/40 - 6/40 + 25/40
= 55/40 = 11/8