This is a calculator that I wrote while I was taking Linear Algebra. My brother had an HP 48G that I really liked. It was stack based and the input made sense to me. The only problem I found was that it didn't handle fractions well. Everything had to be floating point numbers, but I wanted fractional answers. This made me decide to write my own calculator. This handles all numbers as fractions and it can handles matrices and does many common matrix operations. It also has the ability to store items as variables. I also wrote a web-based interface which is included in the downloadable source.