Tính: a) (– 15) . 4 – 240 : 6 + 36 : (– 2) . 3; b) (– 2^5) + [(– 69) : 3 + 53)] . (– 2) – 8

* Hướng dẫn giải

a) (– 15) . 4 – 240 : 6 + 36 : (– 2) . 3

= – (15 . 4) – 40 + [– (36 : 2) . 3]

= (– 60) – 40 + [(– 18) . 3]

= (– 60) – 40 + (– 54)

= (– 60) + (– 40) + (– 54)

= – (60 + 40 + 54) 

= – 154. 

b) (– 2⁵) + [(– 69) : 3 + 53] . (– 2) – 8 

= (– 32) + [– (69 : 3) + 53] . (– 2) – 8

= (– 32) + [ (– 23) + 53] . (– 2) – 8 

= (– 32) + (53 – 23) . (– 2) – 8 

= (– 32) + 30 . (– 2) – 8 

= (– 32) + (– 60) – 8 

= – (32 + 60) – 8

= – 92 – 8

= – (92 + 8) 

= – 100.