Random Numbers setup

Hi,

I am playing with the Random Numbers feature and I am wondering if I am doing it right. It works, but I am wondering if I am setting it up correctly.

I created a Variable with the settings of being a number and being Random between 0 - 1000

I put a text box referencing the variable on the slide. To test whenever I load the slide the number changes... so far so good.

Now I want to add a button that whenever I click it, the number changes.

I add the button and choose the options of changing the Variable as in the screenshot. Any other settings wont work. My only question is that I have to add again the Variable range of 0 - 1000 to get it to work. Is this correct or am I approaching it wrong?