Условие:

Реши удобным способом.
45 + 38 + 5 + 2;
6 + 27 + 14 + 3;
12 + 19 + 8 + 1;
16 + 17 + 4 + 3;
17 + 6 + 34 + 3;
25 + 8 + 5 + 42;
13 + 55 + 5 + 7;
9 + 4 + 31 + 56.

45 + 38 + 5 + 2 = (45 + 5) + (38 + 2) = 50 + 40 = 90
 
6 + 27 + 14 + 3 = (6 + 14) + (27 + 3) = 20 + 30 = 50
 
12 + 19 + 8 + 1 = (12 + 8) + (19 + 1) = 20 + 20 = 40
 
16 + 17 + 4 + 3 = (16 + 4) + (17 + 3) = 20 + 20 = 40
 
17 + 6 + 34 + 3 = (17 + 3) + (6 + 34) = 20 + 40 = 60
 
25 + 8 + 5 + 42 = (25 + 5) + (8 + 42) = 30 + 50 = 80
 
13 + 55 + 5 + 7 = (13 + 7) + (55 + 5) = 20 + 60 = 80
 
9 + 4 + 31 + 56 = (9 + 31) + (4 + 56) = 40 + 60 = 100