I was the worst type of high school student: The kind that gets dumber over time rather than showing improvement. I aced Geometry, passed Algebra, started bombing in Trig. By the time we got to Calculus, I did so poorly that I probably made the students around me worse by sheer osmosis.

Geometry is (or at least was) invaluable to an industrial designer doing CAD work, and I still use algebra on a regular basis to figure things out when I'm buying studio supplies in bulk or making stuff. And I just found out there's a free app that can help you with algebra. It's pretty cool, you don't even have to type stuff into your phone:

Called PhotoMath, it's been around for at least a year for iDevices, and earlier this year they released an Android version. Reviews are mostly positive, and as you'd expect, some high school students are using it to cheat. Another reviewer makes this comment:

Newest update says it supports trigonometry problems but it doesn't :/ that part completely fails.

Every time I see the words "trigonometry" and "fails" in the same sentence, I still feel a little twinge.