2+22+23+.......*29=?
Do you mean
21+22+23+...+29 ?
If so, note that there are 9 terms of an arithmetic progression. So, the sum is
9/2 (21+29) = 225
21+22+23+...+29 ?
If so, note that there are 9 terms of an arithmetic progression. So, the sum is
9/2 (21+29) = 225