B. Perform the indicated operation.
16. (-31) + (-13) = _______
17. -48 ÷ (-6) = _________
18. -42 + 19 = _________
19. -9 x -8 = __________
20. 8 x (-3) = _________
21. -20 + (-4) = ________
22. - 4 – (8) = ________
23. 33 - (-6) = _______
24. 3 + (-7) =________
25. 8 + (-7) = ________​