Question

tinh nhanh

1+2+3+4+5+6+7+8+9+11+12+13+14+15+16+17+18+19

Answer 1

1+2+3+4+5+6+7+8+9+11+12+13+14+15+16+17+18+19

=(1+19)+(2+18)+(3+17)+(4+16)+(5+15)+(6+14)+(7+13)+(8+12)+(9+11)

=20+20+20+20+20+20+20+20+20

=20x9

=180

Answer 2

\(1+2+3+4+5+6+7+8+9+11+12+13+14+15+16+17+18+19\)

\(=\left(1+19\right)+\left(2+18\right)+\left(3+17\right)+\left(4+16\right)+\left(5+15\right)+\left(6+14\right)+\left(7+13\right)+\left(8+12\right)+\left(9+11\right)\)\(=20+20+20+20+20+20+20+20+20\)

\(=20\times9\)

\(=180\)

Answer 3

1+2+3+4+5+6+7+8+9+11+12+13+14+15+16+17+18+19

=(1+19)+(2+18)+(3+17)+(4+16)+(5+15)+(6+14)+(7+13)+(8+12)+(9+11)

=20+20+20+20+20+20+20+20+20

=20x9

=180

Answer 4

1+2+3+4+5+6+7+8+9+11+12+13+14+15+16+17+18+19

= (1+19) + (2+18) + (3+17) + (4+16) + (5+15) + (6+14) + (7+13) + (8+12) + (9+11)

= 20 + 20 + 20 + 20 +20 + 20 + 20 + 20 + 20

= 20 x 9

= 180 

Hok tốt!

Answer 5

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 11 + 12 + 13 + 14 + 15 + 16 + 17 + 18 + 19

= (1 + 19) + (2 + 18) + (3 + 17) + (4 + 16) + (5 + 15) + (6 + 14) + (7 + 13) + (8 + 12) + (9 + 11) 

=     20      +    20      +    20      +     20     +        20    +    20      +      20     +    20      +     20

=     20  x 9 

=     180

= 

Answer 6

= (1+19)+(2+18)+(3+17)+(4+16)+(5+15)+(6+14)+(7+13)+(7+13)+(8+12)+(9+11)

= 20+20+20+20+20+20+20+20+20+20

= 20x10

=200