4 friends evenly divided up an n-slice pizza. One friend, Harris, ate 1 fewer slice then he received

Harrison ate n=4/4 slices of pizza.

Explanation

4 friends evenly divided up a - slice pizza.

So, the number of slices each friend received

Now, Harrison ate 1 fewer slice than he received. As he received slices, so 1 fewer than means ...

Thus, Harrison ate n=4/4 slices of pizza.