Question

1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20​

Answer 1

Answer:

210...................

..

.

Answer 2

Answer:

210

Step-by-step explanation:

sum of first n natural numbers is

n(n+1)/2

here first 20 numbers are there so n=20

=20(20+1)/2

=10(20+1)

=10×21

=210