Условие:

Вычисли и проверь решение:
75 + 12
9432
56 + 24
142

75 + 12 = (70 + 5) + (10 + 2) = (70 + 10) + (5 + 2) = 80 + 7 = 87
Проверка:
1) 8712 = 8775 = 805 = 75;
2) 8775 = 87570 = 8270 = 12.
 
9432 = (90 + 4) − (30 + 2) = (9030) + (42) = 60 + 2 = 62
Проверка:
1) 62 + 32 = (60 + 2) + (30 + 2) = (60 + 30) + (2 + 2) = 90 + 4 = 94;
2) 9462 = (90 + 4) − (60 + 2) = (9060) + (42) = 30 + 2 = 32.
 
56 + 24 = (50 + 6) + (20 + 4) = (50 + 20) + (6 + 4) = 70 + 10 = 80
Проверка:
1) 8024 = 80204 = 604 = 56;
2) 56 + 24 = (50 + 6) + (20 + 4) = (50 + 20) + (6 + 4) = 70 + 10 = 80.
 
142 = (10 + 4) − 2 = 10 + (42) = 10 + 2 = 12.
Проверка:
1) 12 + 2 = (10 + 2) + 2 = 10 + (2 + 2) = 10 + 4 = 14;
2) 1412 = (10 + 4) − (10 + 2) = (1010) + (42) = 0 + 2 = 2.