Question

Tính nhanh : 

-13.21-13.80+13

-1+2-3+4-5+6-...-2021+2022

Answer 1

-13.21-13.80+13

=-13.(21-80+1)

=-13.100

=-1300

-1+2-3+4-5+6-...-2021+2022

=(-1+2)+(-3+4)+...+(-2021+2022)

=1+1+1+...+1 (1011 số hạng)
=1011

 

 

Answer 2

-13 . 21 - 13 . 80 + 13

13 ( -21 - 80 + 1 )

13 . ( -100 )

- 1300

 

Answer 3

\(-13\cdot21-13\cdot80+13=13\left(-21-80+1\right)=13\cdot\left(-100\right)=-1300\)

Answer 4

-13.21-13.80+13

=-13.21-13.(-80)-(-13)

=-13.\(\left[21.\left(-80\right)\right]\)

=-13.-1680

=21840