Question

10 + 20 + 30 + 40 + 60 + 80 + 70 + 90 

Answer 1

ket qua bang 320

Answer 2

10 + 20 + 30 + 40 + 60 + 80 + 70 + 90

= (10 + 90) + (20 + 80) + (30 + 70 ) + (40 + 60)

=      100    +      100    +      100    +      100

=                    400

Answer 3

nham ket qua bang 400 nha

Answer 4

\(10+20+30+40+50+60+70+80+90\)

\(=\left(10+90\right)+\left(20+80\right)+\left(30+70\right)+\left(40+60\right)+50\)

\(=100+100+100+100+50\)

\(=100.4+50\)

\(=400+50\)

\(=450\)

Answer 5

\(10+20+30+40+60+80+70+90\)

\(=\left(10+90\right)+\left(20+80\right)+\left(30+70\right)+\left(40+60\right)\)

\(=100+100+100+100\)

\(=400\)

Answer 6

(10+90)+(20+80)+(30+70)+(40+60)

=100   +    100   +   100  +    100

=100*4

=400

Answer 7

10 + 20 + 30 + 40 + 60 + 70 + 80 + 90

= [(1 + 9) + (2 + 8) + (3 +7) + (4 + 6)] x 10

= [10 + 10 + 10 + 10] x 10

= [10 x 4] x 10

= 40 x 10

= 400

nha bn

Mk làm theo cách khác nha

Answer 8

10+20+30+40+50+60+70+80+90

=(10+90)+(20+80)+(30+70)+(40+60)+50

=100+100+100+100+50

=100.4+50

=400+50

=450

Answer 9

biết rồi còn hỏi