Tính nhanh: a) -2001 + (1999 + 2001); b) (43 - 863) - (137 - 57)?

Question

a, -2001 + (1999 + 2001)
b, (43 - 863) - (137 - 57)

Answer 1

a, -2001 + (1999 + 2001)

=(-2001)+1999+2001         (phá ngoặc)

=(-2001)+2001+1999

=0+1999=1999

b, (43 - 863) - (137 - 57)

= -820-80

= -900

 

Answer 2

a) -2001 + (1999 + 2001)

= [ (-2001) + 2001] + 1999

= 1999

b) (43 - 863) - (137- 57)

= -820 - 80

= (-820) - (-80)

= -900

Answer 3

a) -2001+(1999+2001)

= 1999+(-2001+2001)

= 1999+0

=1999

b) (43-863)-(137-57)

= -820-80

= -900

Chức bạn học tốt 

Answer 4

-2000+(1999+2001)

=- 2000+4000

=1999

(43-863) - (137-57)

= -820-80

=-900

Answer 5

a, - 2001 + ( 1999 + 2001 )

= - 2001 + 1999 + 2001

= ( - 2001 + 2001 ) + 1999

= 0 + 1999

= 1999

b, ( 43 - 863 ) - ( 137 - 57 )

= 43 - 863 - 137 + 57

= ( 43 + 57 ) - ( 863 + 137 )

= 100 - 1000

= - 900