Question

Tực hiện phép tính:

11 + 12 + 13 + 14 + 15 + 16 + 17 + 18 + 19

Answer 1

11 + 12 + 13 + 14 + 15 + 16 + 17 + 18 + 19

= (11 + 19) + (12 + 18) + (13 + 17) + (14 + 16) + 15

= 30 + 30 + 30 + 30 + 15

= 120 + 15

= 135

Answer 2

\(11+12+13+14+15+16+17+18+19\)

\(\Leftrightarrow\left(11+19\right)+\left(12+18\right)+\left(13+17\right)+\left(14+16\right)+15\)

\(\Leftrightarrow30+30+30+30+15\)

\(\Leftrightarrow\left(30.4\right)+15\)

\(\Leftrightarrow120+15=135\)

Answer 3

= (11 + 19 ) + ( 12 +18 )  ( 13 + 17 ) ( 14 + 16 ) + 15

= \(30+30+30+30+15\)

= \(30\times4+15\)

\(=120+15=135\)

Answer 4

Ta có:

(11+19)+(12+18)+(13+17)+(14+16)+15

=30+30+30+30+15

=60+60+15

=120+15

=135

Answer 5

(19+11).9:2=135

nho cho minh nhe