Question

11+12+13+14+15+16+17+18+19+20+...+29+30

Answer 1

[(30-11):1+1].(30+11):2=410

Answer 2

Nhớ tích cho mk nhé!

Answer 3

11+12+13+14+15+16+17+18+19+......+29+30

=(11+30)+(12+29)+(13+28)+..........+(19+22)+(20+21)

=41+41+41+...........+41+41

=41.((30-11)/1+1)

=41.20

=820

CHÚC BN HOK TỐT NHA

Answer 4

(11+29)+(12+18)+(13+17)+(14+16)+(15+15)+30

= 30 + 30 + 30 + 30 + 30 + 30

=180