Question

20 + 40 + 60 + 80 + 100 + 120 + 140 +160 + 180

tính bằng cách thuận tiện nhất

Answer 1

20 + 40 + 60 + 80 + 100 + 120 + 140 +160 + 180

= (20 + 180) + (40 + 160) + (60 + 140) + (80 + 120) + 100

= 200 + 200 + 200 + 200 + 100

= 900

Answer 2

(20+180)+(40+160)+(60+140)+(80+120)+100

200       + 200       + 200      + 200       + 100=900

Answer 3

( 20 + 180 ) + ( 40 + 160 ) + ( 60 + 140 ) + ( 80 + 120 ) + 100 

= 200 + 200 +200 +200 + 100

 = 900

Answer 4

20 + 40 + 60 + 80 + 100 + 120 + 140 +160 + 180

= (20 + 180) + (40 + 160) + (60 + 140) + (80 + 120) + 100

= 200 + 200 + 200 + 200 + 100

= 900

Answer 5

20 + 40 + 60 + 80 + 100 + 120 + 140 +160 + 180

= (20 + 180) + (40 + 160) + (60 + 140) + (80 + 120) + 100

= 200 + 200 + 200 + 200 + 100

= 900

Answer 6

20 + 40 + 60 + 80 + 100 + 120 + 140 +160 + 180

= (20 + 180) + (40 + 160) + (60 + 140) + (80 + 120) + 100

= 200 + 200 + 200 + 200 + 100

= 900

Answer 7

20 + 40 + 60 + 80 + 100 + 120 + 140 +160 + 180

= (20 + 180) + (40 + 160) + (60 + 140) + (80 + 120) + 100

= 200 + 200 + 200 + 200 + 100

= 900

Answer 8

20 + 40 + 60 + 80 + 100 + 120 + 140 +160 + 180

= (20 + 180) + (40 + 160) + (60 + 140) + (80 + 120) + 100

= 200 + 200 + 200 + 200 + 100

= 900

Answer 9

20 + 40 + 60 + 80 + 100 + 120 + 140 +160 + 180

= (20 + 180) + (40 + 160) + (60 + 140) + (80 + 120) + 100

= 200 + 200 + 200 + 200 + 100

= 900

Answer 10

20+40+60+80+100+120+140+160+180

=(20+180)+(40+160)+(60+140)+(80+120)+100

=200+200+200+200+100

=900

Answer 11

20 + 40 + 60 + 80 + 100 +120 +140 + 180

=(120 + 80) + (160+ 40) + (180 + 20)  +100

=200 + 200 +200 + 100

=900

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Answer 12

( 180 +20) + (160+40 ) +(140 + 60 ) + ( 120+80 ) +100=900

Answer 13

120+280+260+340=1000

Answer 14

\(20+40+60+80+100+120+140+160+180\)

\(=\left(20+180\right)+\left(40+160\right)+\left(60+140\right)+\left(80+120\right)+100\)

\(=200+200+200+200+100\)

\(=800+100\)

\(=900\)

Học Tốt !