4-digit 5's complement of a negative number

Question

Let $n = -13, \ k = -24$

How do I find the 4-digit 5's complement of each number? What would be the result of $n + k$ in complement representation?

I understand how to calculate $n$-digit, 2's complement. I convert it to base 2, invert and add one.

Also, with positive numbers, let's say $n = 13, \ k = 24$, the 4-digit 5's complement would be $(5542)_{10}$ and $(5531)_{10}$. Correct? What would their addition be?