6+5+8+1=3 3+8+6+9=4 8+0+6+7=4 5+4+1+6=1 2+6+8+9=?

6 + 5 + 8 + 1 = (6 + 5) + (8 + 1) = 11 + 9 = 20;

33 + 8 + 6 + 9 = (33 + 8) + 9 + 6 = ((33 + (7 + 1)) + 9 + 6 = (33 + 7 + 1) + 9 + 6 = 33 + 7 + 1 + 9 + 6 = (33 + 7) + (1 + 9) + 6 = 40 + 10 + 6 = (40 + 10) + 6 = 50 + 6 = 56;

48 + 0 + 6 + 7 = 48 + 6 + 7 = 48 + (2 + 4) + 7 = 48 + 2 + 4 + 7 = (48 + 2) + 4 + (6 + 1) = 50 + 4 + 6 + 1 = 50 + (4 + 6) + 1 = 50 + 10 + 1 = 60 + 1 = 61;

45 + 4 + 1 + 6 = 45 + (4 + 1) + 6 = 45 + 5 + 6 = (45 + 5) + 6 = 50 + 6 = 56;

12 + 6 + 8 + 9 = (12 + 8) + 9 + (1 + 5) = 20 + 9 + 1 + 5 = 20 + (9 + 1) + 5 = 20 + 10 + 5 = 30 + 5 = 35.

Ответ:  6 + 5 + 8 + 1 = 20;

           33 + 8 + 6 + 9 = 56;

           48 + 0 + 6 + 7 = 61;

           45 + 4 + 1 + 6 = 56;

           12 + 6 + 8 + 9 = 35.