a) (4 + 32 + 6) + (10 – 36 - 6)
= 4 + 32 + 6 + 10 – 36 – 6
= 52 – 42
= 10
b) (77 + 22 – 65) - (67 + 12 - 75)
= 77 + 22 – 65 – 67 – 12 + 75
= 77 – 62 + 22 – 12 + 75 – 65
= 10 + 10 + 10
= 30
c) - (-21 + 43 + 7) – (11 – 53 - 17)
= 21 – 43 – 7 – 11 + 53 + 17
= 21 – 11 + 53 – 43 + 17 – 7
= 10 + 10 + 10
= 30