One fifth of the square of a number

One fifth of the square of a number

We have an algebraic expression. Let's break this into parts.

1. The phrase a number means an arbitrary variable, let's call it x
2. The square of a number means we raise it to the power of 2. So we have x^2
3. One-fifth means we have a fraction, where we divide our x^2 in Step 2 by 5. So we get our final answer below:

x^2/5