To change an input, just click on the variable. Once you change the variables you want, click the "Go" button associated with that row.
I wrote this to demonstrate how to do logs, exponents, and roots with existing blocks in Scratch. You can see the proof I used for exponents at http://i.cubeupload.com/wdYVpW.jpg You are also welcome to use the scripts from this project if you need them, but please give me credit.
