Question

what is sum of first 20 odd natural numbers don't add it tell me by formula​

Answer 1

Step-by-step explanation:

answer is 400.........

Answer 2

Step-by-step explanation:

Sn = n/2(2a+(n-1)d)

S20 = 20/2(2(1)+19(2). (d = 2, first odd number=1 second is 3, 3-1 = 2)

S20 = 10(2+38)

S20 = 400