Socio-economic situations are a rough thing, and are unfair to a lot of kids. Education is not a priority in many of my students' households, so if I tried to require them to purchase a calculator (even a $35 scientific one), I'd get a lot of blank stares. This makes homework assignments challenging since Pre-Cal loves trig and trig values outside of unit circle points are not intuitive to guess. So I made this. It's a table of sin/cos/tan values for all the angles between 0 and 180. A simple sign flip will net 181 through 360. I'm planning on distributing these when we get to trig. It should improve accuracy (my kids LOVE to round too much and too soon), especially when they calculate a trig inverse. It also might help better equate the meaning of a trig inverse operation.

Trig Table: Excel 2008 PDF