Question

without adding find the sum of 1 + 3 + 5 + 7 + dash + 23​

Answer 1

Heya!!

The given series is in A.P becoz Common Difference is same.

So, it's sum is given by

S23 = n/2{ a + L }

Sn sum of 23 terms.

n is number of terms

a is ist term

And L is last term.

S23 = 12/2 { 1 + 23 }

S23 = 6 × 24

S23 = 144