We can solve a question like "counting the numbers between range which follow some properties" using Digit DP, like count the n digit number whose sum of digits is divisible by 3.

But how can we solve, "sum of the numbers between range which follow some properties" like "sum of n digit numbers whose digit sum is divisible by k". constraints: n = 1e5, 2 <= k <= 10

Please give me a link where I can read about how to solve these types of problems.