Ответ:

  1. 9 · 70 = 630; 630 − 30 = 600; 600 : 12 = 50; 50 + 50 = 100.

  2. 102 + 8 = 110; 110 : 5 = 22; 22 · 20 = 440; 440 − 40 = 400.

  3. 400 · 7 = 2800; 2800 + 2200 = 5000; 5000 : 250 = 20; 20 + 80 = 100.

  4. 34 · 5 = 170; 170 + 230 = 400; 400 : 80 = 5; 5 + 95 = 100.

Ответ: 1) 100; 2) 400; 3) 100; 4) 100.