Colorblind Math

On Friday I was helping a student with math. We were trying to add 7+3. I was using my fingers to add 7+3. The student was not getting it so I colored 7 of my fingernails green with a marker. I colored the other 3 fingernails orange. I had the student count the 7 green fingers first. As he was counting I realized that he was colorblind and that he could not differentiate between green and orange. My plan was foiled and I ended up with colored fingernails. Bummer dude.