Ответ:

  1. −9 · 8 = −72.
  2. −18 : (−6) = 3.
  3. 12 · (−5) = −60.
  4. −48 : 8 = −6.
  5. −3 · (−14) = 42.
  6. (−3/4) · (−4/7) = 12/28 = 3/7.
  7. (−7/8) : (−3/8) = (−7/8) · (−8/3) = 7/3.
  8. (−5/6) · 6 = −5.
  9. −100 + 58 = −42.
  10. −39 + (−89) = −128.
  11. 38 − 67 = −29.
  12. −70 − (−221) = −70 + 221 = 151.
  13. −67 + (−89) + 67 = (−67 + 67) − 89 = −89.
  14. 13 − 9 − 93 = 4 − 93 = −89.
  15. −73 · 8 · (−125) = −73 · (−1000) = 73000.
  16. 1 + (−1/4) = 3/4.
  17. −1/3 − (−1/2) = −1/3 + 1/2 = 1/6.
  18. 3/8 − 3/4 = 3/8 − 6/8 = −3/8.
  19. (−2)³ − 3² = −8 − 9 = −17.
  20. (−5)² + 2³ = 25 + 8 = 33.