(3/8 + 4 1/3) · 240 = (3/8 + 13/3) · 240 = 3/8 · 240 + 13/3 · 240 = 3 · 30 + 13 · 80 = 90 + 1040 = 1130
(6 2/3 - 4 3/4) · 3 21/25 = (20/3 - 19/4) · 96/25 = 20/3 · 96/25 - 19/4 · 96/25 = 4/1 · 32/5 - 19/1 · 24/25 = 128/5 - 456/25 = (640 - 456)/25 = 184/25 = 7 9/25