Условие:

43 + 50
62 + 4
31 + 6
24 + 40

43 + 50 = (40 + 3) + 50 = (40 + 50) + 3 = 90 + 3 = 93
62 + 4 = 60 + (2 + 4) = 60 + 6 = 66
31 + 6 = (30 + 1) + 6 = 31 + 6 = 37
24 + 40 = (20 + 40) + 4 = 60 + 4 = 64