The sum of numbers between 100 and 200 which are divisible by 9 is

First, identify the numbers between 100 and 200 divisible by 9.
The first term is 108 (9 × 12) and the last term is 198 (9 × 22).
This forms an arithmetic progression with a common difference of 9.
Calculate the number of terms: n = ((198 - 108) / 9) + 1 = 11.
Use the sum formula S_n = n/2 * (first + last).
Sum = 11/2 * (108 + 198) = 11/2 * 306 = 11 * 153 = 1683.