How can you get "5" from the numbers "21, 13, 9, 6, 4" and by only using each operation once?

Question

I can only use each number "21, 6, 4, 13 and 9" once but I must get 5 for my answer. I can use multiplication, division, addition, and subtraction. Only problem is I do not know how to solve.

Answer 1

(21/(9-6)+13)/4=5