Question

without adding find the sum1+3+5+7+9​

Answer 1

You can find the sum by multiplying the no. of terms and the average.

Here the average is the middle term, so it is 5, and the no. of terms is 5. So the sum is 5 × 5 = 25.

Answer 2

Answer:

1+3+5+7+9 = (5)²

[Sum of first five odd numbers] = 25