Ответ:

  1. 57 × 8 = 50 × 8 + 7 × 8 = 400 + 56 = 456.

  2. 94 × 6 = 90 × 6 + 4 × 6 = 540 + 24 = 564.

  3. 120 × 7 = 12 × 7 × 10 = 84 × 10 = 840.

  4. 38 × 20 = 38 × 2 × 10 = 76 × 10 = 760.

Ответ: 456; 564; 840; 760.