Question

tinh nhanh 1+2+3+4+5+6+7+8+9

Answer 1

1+2+3+4+5+6+7+8+9

=(1+9)+(2+8)+(3+7)+(4+6)+5

=10+10+10+10+5

=45

Answer 2

1+2+3+4+5+6+7+8+9

=(1+9)+(2+8)+(3+7)+(4+6)+5

=10+10+10+10+5

=45

K mình mình k lại

Answer 3

1+2+3+4+5+6+7+8+9 = 45 

Answer 4

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9

= (1 + 9) + (2 + 8) + (3 + 7) + (4 + 6) + 5

= 10 + 10 + 10 + 10 + 5

= 45

Answer 5

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9

= ( 1 + 9 ) + ( 2 + 8 ) + ( 3 + 7 ) + ( 4 + 6 ) + 5

= 10 + 10 + 10 + 10 + 5

= 40 + 5

= 45

Answer 6

Tính nhanh :  1+2+3+4+5+6+7+8+9 = 45

Answer 7

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9

= (1 + 9) + (2 + 8) + (3 + 7) + (4 + 6) + 5

= 10 + 10 + 10 + 10 + 5

= 45

Answer 8

 1+2+3+4+5+6+7+8+9

=(1+9)+(2+8)+(3+7)+(4+6)+5

=10+10+10+10+5

=10*4+5

=40+5

=45

Answer 9

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9

​= ( 1 + 9 ) + ( 2 + 8 ) + ( 3 + 7 ) + ( 4 + 6 ) + 5

​= 10 + 10 + 10 + 10 + 5

​=45

​

Answer 10

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9
= (1 + 9) + (2 + 8) + (3 + 7) + (4 + 6) + 5
= 10 + 10 + 10 + 10 + 5
= 45

Answer 11

  1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9

= ( 1 + 9 ) + ( 2 + 8 ) + ( 3 + 7 ) + ( 4 + 6 ) + 5

= 10 + 10 + 10 + 10 +5

= 10 x 4 + 5

= 45

Answer 12

=(1+9)+(2+8)+(3+7)+(4+6)+5

=10+10+10+10+5

20+20+5

=45
 

Answer 13

   1 + 2 + 3 +4 +5 +6 +7 +8 +9

= ( 1 +9 ) + ( 2+8 ) + ( 3+7 ) + ( 4 + 6) +5

=  10      +   10      +   10     +     10     + 5

= 10*4+5

= 40 + 5

=45

Answer 14

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 

= ( 9 + 1 ) + ( 8 + 2 ) + ( 7 + 3 ) + ( 6 + 4 ) + 5

= 10 + 10 + 10 + 10 + 5 

= 45

Answer 15

tinh nhanh 1+2+3+4+5+6+7+8+9=45

Answer 16

1+2+3+4+5+6+7+8+9

=( 1+9) + (2+8) + (3+7) + (4+6) + 5

= 10    +    10    +  10   +   10   +  5

= 10      *      4       +       5

=          40              +       5

=                        45

Answer 17

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9

= (1 + 9) + (2 + 8) + (3 + 7) + (4 + 6) + 5

= 10 + 10 + 10 + 10 + 5

= 45