This year we have had the honor of piloting 1:1 iPads for Freshmen. One of the projects I created was a transparent graph that can be placed over a photo in Notability. The app itself is amazing and you should definitely check it out if you haven’t. Students were instructed to take a picture of something that demonstrated slope and they brought them to class on their iPad. I had them import the .note file (attached) with the transparent graph and they replaced my picture with theirs. We then took notes over slope using their photo. It was an awesome project and we have used this process for systems of of equations and will use it again for graphing parabolas.
This project was originally posted on SJSDMath.posterous.com but all of my Posterous content will be moved to this blog as Posterous will no longer exist.
Infinitely Teaching 
This is great! I just finished teaching my 7th grades about linear equations, and I used geogebra to do something similar. I love the idea of doing it on an ipad and using notability.
Thanks for sharing!
How did you make the transparent graphs?
I dropped the background out in Photoshop and saved it as a transparent gif. I never have trouble with it in Notability, but some of my students did so I provided them with the Notability file. They took pictures on their iPad and swapped my picture with theirs. I provided the .note file in the blog post. You can save the pic to your camera roll and use it when you want. It will look partially black in the camera roll, but should import transparent.
I used Photoshop and dropped out the background and used the select tool to delete the white boxes and saved it as a transparent gif. You can also select by color range instead if selecting each box.