Question

tính nhanh 

a) 214 +[ 120- ( 214 +120)]

b) ( -321 ) -[ ( -321 +35 ) -235 ]

Answer 1

a) 214 + [ 120 - ( 214 + 120 ) ]

= 214 + [ 120 + ( -120 ) + ( -214 ) ]

= 214 + [ 0 + (-214 ) ]

= 214 + ( -214 )

= 0

b) ( - 321 ) - [ ( -321  + 35 ) - 235 ]

= -321 ) - [ ( -321 ) + ( -35 ) + 235 ]

= -321 - [ -321 + 200 ]

= -321 + 321 + 200

= 0 + 200

= 200

Answer 2

a)214+[120-(214+120)]

=214+120-214-120

=[(-214)+214]+[120+(-120)]

=0+0=0