Question

Tính nhanh:

1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19

Answer 1

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

=20+20+20+20+20+20+20+20+20+10

=20×9+10

=180+10

=190

Answer 2

( 19 + 1) x 19 : 2 = 190

Answer 3

1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19=190

Answer 4

190 nha bn

Answer 5

Tính nhanh:

   1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 + 14 + 15 + 16 + 17 + 18 + 19

= ( 19 + 1 ) + ( 2 + 18 ) + ( 3 + 17 ) + ( 4 + 16 ) + ( 5 + 15 ) + ( 6 + 14 ) + ( 7 + 13 ) + ( 8 + 12 ) + ( 9 + 11 ) + 10 

= 20 + 20 + 20 + 20 + 20 + 20 + 20 + 20 + 20 + 10

= 20 x 9 + 10

= 180 + 10

= 190

Answer 6

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

=     20   x 9  + 10

=        180     + 10 =  190

                           Chúc bạn học tốt.