(19/24-4/15)-(7/10-6/15)
(19/24 - 4/15) - (7/10 - 6/15) = 9/40 1) 19/24 - 4/15 = 95/120 - 32/120 = 63/120 2) 7/10 - 6/15 = 21/30 - 12/30 = 9/30 3) 63/120 - 9/30 = 63/120 - 36/120 = 27/120 = 9/40