Question

Find the sum of all three-digit numbers which are divisible by 9..
Class 10 AP​

Answer 1

Step-by-step explanation:

The series starts from 108 and ends with 999

The series is 108,117....999

Now find the sum

a=108,d=9,l=999

Now find An

Sn=n/2[a+l]

To find "n" value

n=(l-a/d)+1

=(999-108/9)+1

=(891/9)+1

=(99)+1

=100

Now

Sn=n/2[a+l]

=100/2[108+999]

=50[1107]

=55350