Question

Without actual addition find the sum of 1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17

Answer 1

Heya !!!

Here is Your Answer.

Given :
1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17

We know that ...
Sum of n odd numbers = n²

So, in 1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17,
there are 9 consecutive odd numbers.

Therefore,
1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 = 9²
= 81.

Hope It Helps

Answer 2

Heya !!!

Sum of n odd numbers = (N)²

1+3+5+7+9+11+13+15 +17 = (N)²

There are 9 consecutive odd numbers.

Therefore,

1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 = (9)²

=> 81

HOPE IT WILL HELP YOU..... :-)