Question

1) Tính nhanh

a) (-8-12):|-5|

b) (-49)-|-145|+(-2017)+|245|+(-51)

c) 79.|-39|-21.|-39|

d) -99(2-678)-678.99

 

Answer 1

a,(-8-12):/-5/=-20:5=4(ban oi con nay ko tinh nhanh dc)

b,(-49)-/-145/+(-2017)+/245/+(-51)=(-49+am 51)-145-2017+245=-100+100-2017=0-2017=-2017

c lam theo con gai obama minh ko chac ban tinh lai ket qua xem

d,-99(2-678)-678.99=-99.676+678.(-99)=-99.676+678.(-99)=-99(676+678)=-99.1345=-133155(tinh lai ket qua nha)

Answer 2

c) 79.l-39l -21.l-39l

=79.39 -21.39

=39.(79 -21)

=39.58=3364

Answer 3

a) (- 8 - 12 ) : | - 5 | = - 20 : 5 = - 4

b) ( - 49 ) - | - 145 | + ( - 2017 ) + | 245 | + ( - 51 )

=  - 49  - 145 - 2017 + 245 - 51

= ( - 49 - 51 ) + ( - 145 + 245 ) - 2017

= - 100 + 100 - 2017

=  0 - 2017 = - 2017

c) Bạn cho đề rõ ra nhé !!!!

d) - 99 . ( 2 - 678 ) - 678 . 99

= - 99 . ( - 676 ) - 67122

= 66924 - 67122

= - 198