Question

without actual addition find the sum 1+3+5+7+9+11+13+15

Answer 1

sum of first n odd natural nos =
$n {}^{2}$
So, sum of 1st 8 odd numbers= 8×8 =64

Answer 2

Answer:

sum of first n odd natural nos =

n {}^{2}n

2

So, sum of 1st 8 odd numbers= 8×8 =64