The phrase

*3 numbers*means we choose

*3*arbitrary variables. Let's call them x, y, z.

The sum of of these 3 numbers is:

x + y + z

The phrase

*its product*means we multiply all 3 arbitrary variables together:

xyz

Now, the phrase

*divided by*means we divide x + y + z by xyz:

**(x + y + z)/xyz**