Question

Tính nhanh

a) (42 – 98) – (42 – 12) - 12

b) (– 5) . 4 . (– 2) . 3 . (-25)

Answer 1

a/ (42 – 98) – (42 – 12) -12

= 42 – 98 – 42 + 12 - 12

= (42 – 42) + (12 -12) – 98 

= - 98

b/ (–5) . 4 . (– 2) . 3 . (-25) 

= [(-5).(-2)].[4.(-25)].3

= - 3000

Answer 2

a/ (42 – 98) – (42 – 12) -12

= 42 – 98 – 42 + 12 - 12

= (42 – 42) + (12 -12) – 98 

= 0 + 0 - 98

= - 98

b/ (–5) . 4 . (– 2) . 3 . (-25) 

= [(-5).(-2)].[4.(-25)].3

= 10 . ( - 100 ) .3

= - 3000