LiteralMath
Text editor with the additional capabilities of math notation and hypertext, aimed at the high school / college environment. Uses the RTF format known to Wordpad, Word. Generates HTML, so that math notation can be displayed by popular browsers. Users may specify links to other web documents... Math notation is based on special fonts, thereby allowing browsers to render math at the speed of text. ... Very useful for math communication over the web, with clarity, simplicity, and efficiency.
http://www.literal.eng.br/LMath24.exe - 2Mb - Download - Screenshot

vCalc
vCalc is a keyboard driven scientific calcualtor, that works using the RPN notation common in well known scientific calculators. It supports a complete set of math, binary and statistical operations. * Keyboard driven user interface * Four basic operations on integer and floating point numbers...
http://www.icegiant.com/downloads/vcalc.exe - 804Kb - Download - Screenshot

Scientific Letter
Scientific Letter is a scientific mailer. It allows the user to create scientific mail messages with complex equations. This modern and beautiful scientific software makes the exchange of complex ideas simple. The scientific equation editor used in this software allows you to create complex... The recipient of a mail message from Scientific Letter by someone using another mailer will see the message text with equations included in it in LaTeX notation. ... Mailer features: + Equations may be extremely complex + Highest quality scientific equation display + Beautiful design + Fine usability...
http://www.sciletter.com/demo/scisetup.exe - 321Kb - Download - Screenshot

Chord Pickout
A friend of mine has perfect pitch. He is a professional guitarist. The only instrument he needs to guess chords for a song is his own ear. He can listen to a song and easily pick out the right chords or even make a better arrangement than those he listened to. ... While most of its competitors use simple patterns to recognize chords, Chord Pickout applies complex math and shows outstanding results even in the toughest cases. ... The process is fully automated. ... Chord Pickout will transcribe the music and write down the recognized chords.
http://www.chordpickout.com/download/ChordPickoutSetup.exe - 777Kb - Download - Screenshot

Kalkulator
The Mother of all Calculators, a Swiss Army knife for scientists and engineers. Perhaps the most capable scientific/engineering calculator for Windows. On one hand, this is a calculator: evaluates expressions with more than 100 functions (trig/inverse, log/exp, statisical distributions, Euler,... There ara also unit conversions, physical constants, computer math (binary, octal, hex), and function graphs included. ... Expressions are entered in the customary algebraic notation, and only then evaluated.
http://www.wrotniak.net/works/kalkulator/_zip/kalkulator-inst.exe - 956Kb - Download - Screenshot

RPN Engineering Calculator
This RPN calculator offers 250 solutions with six unique keypads. It has a complete help system with individual tips for all but the most ordinary functions and a Tip of the Day feature for new users. You can select fixed, scientific or engineering notation and degrees, radians, or grads as... ), and some unique to itself: a simple math teaching aid for kids, Wind Chill calculator, and more. ... Binary; is used to manipulate unsigned Binary integers of various lengths (word size) from 4 to 64 bits, about 28 functions are available.
http://www.j-a-associates.com/DnLoads/rpn.zip - 1Mb - Download - Screenshot

#Calculation Component
#Calculation component is a powerful calculation engine for your applications. This ActiveX component integrates expression parsing and evaluation. Generally speaking, #Calculation is very useful in two main areas: first, when a formula has to be defined and evaluated at runtime (for example,... #Calculation Component supports conventional math, string, date&time, logical operators and functions, and is suitable for heavy-duty number crunching. ... It also allows defining variables and sets of related formulas that implement spreadsheet-like recalculations.
http://www.devom.com/downloadqk/sc.zip - 523Kb - Download - Screenshot