calculator

As a programmer and father of two schoolkids, i need about four different calculators and then some that don't seem to exist: Convert to binary, display results as fractions, tell me hex values, check homework, ...

While most of these functions will be addressed in future updates, this is what the calculator already manages:

- Basic calculations plus percent
- Some scientific functions such as quotients and roots
- Parentheses such as (2 + 3) * 4 = 20
- Mathematical constants such as π and e
- Binary, octal, hexadecimal and decimal representation
- display result as fraction such as 1/2 + 3/4 = 5/4
- help!