Without adding, find the sum: i) `1+3+5+7+9\ ` ii) `\ ``1+3+5+7+9+11+13+15+17+19` iii) `1+3+5+7+9+11+13+15+17+19+21+23`

Explanation

(i) In the first series we are given `5` terms having difference `2` between two consecutive numbers.
Therefore, their sum will be:
`5^2=25`

(ii)In the second series we are given `10` terms having difference `2` between two consecutive numbers.
Therefore, their sum will be:
`10^2=100`

(iii)In the third series we are given `12` terms having difference `2` between two consecutive numbers.
Therefore, their sum will be:
`12^2=144`.