Question

Tính nhanh :

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

Answer 1

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

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

A = 100 + 100 + 100 +100 + 50

A = 400 + 50

A = 450

chúc bn hk tốt nhé !

Answer 2

A = 450 nhé

Answer 3

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

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

   \(=100+100+100+100+50\)

   \(=100\times4+50\)

   \(=400+50\)

   \(=450\)

Vậy \(A=450\)

Học tốt #

Answer 4

A = 450 nhé !

Answer 5

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

A=100+100+100+100+50

A=450

Answer 6

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

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

A=   100    +   100     +  100     +    100    +  50

A= 100 × 4 +50

A= 400 + 50

A= 450       

Answer 7

A =450

Answer 8

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

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

A=100+100+100+100+50

A=400+50

A=450

Answer 9

là 450