The Altarians use an interesting number system.

In Altarian, the natural numbers 1 to 5 are written r, s, sr, s/s, and ss. For what it's worth, the Altarians use z for 0.

Thus, s/s+ss=sr/sr and ssr+sr/sr=s/s/s/s. Obviously, s/s*ss=s/s/ss.

Give the Altarian equivalents of the Earth numbers 21 and 36.

Too easy? How about 37 and 38?