Условие:

13 + 6
81 + 5
42 + 6
30 + 24
53 + 10
65 + 30
4 + 73
20 + 73

13 + 6 = (10 + 3) + 6 = 10 + (3 + 6) = 10 + 9 = 19
81 + 5 = (80 + 1) + 5 = 80 + (1 + 5) = 80 + 6 = 86
42 + 6 = (40 + 2) + 6 = 40 + (2 + 6) = 40 + 8 = 48
30 + 24 = 30 + (20 + 4) = (30 + 20) + 4 = 50 + 4 = 54
53 + 10 = (50 + 10) + 3 = 60 + 3 = 63
65 + 30 = (60 + 5) + 30 = (60 + 30) + 5 = 90 + 5 = 95
4 + 73 = 4 + (70 + 3) = 70 + (4 + 3) = 70 + 7 = 77
20 + 73 = (20 + 70) + 3 = 90 + 3 = 93