Wabbitemu
Wabbitemu makes your NumWorks calculator behave like a TI-84!
How to get a ROM
You are not allowed to download a ROM from the internet. However, you can dump your own calculator's ROM. (there are plenty of tutorials on the internet). You can also download a ROM from the internet, but we can't help you with that.
Download
You can download the Wabbitemu app from this link:
Installation
To install the Wabbitemu app, follow the instructions in the how to install guide.
Source code
Source code for Wabbitemu is unfortunately missing, as it's creator (ScarlettSpell) published it only in compiled version.