Let's denote the son's age as \(s\) and the man's age as \(m\). From the problem, we have two equations:

1. \(m = 4s\) (the man is four times as old as his son)
2. \(m - s = 36\) (the difference between their ages is 36 years)

We can substitute equation 1 into equation 2 to solve for \(s\):

\(4s - s = 36 \Rightarrow 3s = 36 \Rightarrow s = 12\)

Substituting \(s = 12\) into equation 1 gives \(m = 4 \times 12 = 48\).

Therefore, the sum of their ages is m + s = 48 + 12 = 60 years.