Q12 of 202 Page 9

Find the sum of first n odd natural numbers.

a = 1, d = 2

Sum of first n odd numbers, Sn = [2a + (n – 1) d]


= [2(1) + (n – 1) 2]


= n [1 + n – 1]


= n2


More from this chapter

All 202 →
10

Find the sum of first 22 terms of an A.P. in which d = 22 and a22 = 149.

 11

Find the sum of all natural numbers between a and 100, which are divisible by 3.

 13

Find the sum of all odd numbers between

(i) 0 and 50


(ii) 100 and 200

 14

Show that the sum of all odd integers between 1 and 1000 which are divisible by 3 is 83667.