http://www.hypermake.com/english/4allcalc.html
"4allCalc is an all purpose calculator with scientific functions, easy transfer to/from the clipboard (Variable "Z"), variables, regression, numeric forms for programmers (binary, octal, hexadecimal), overflow simulation, detailed error messages, online help. Shareware 25$ or 20 EUR. English and German."
Source: OS2.jp