fxopt is a plugin for GCC that converts floating-point functions to fixed-point arithmetic, primarily for implementation in embedded, real-time systems without floating-point hardware. The conversion is performed in GCC's "middle-end", after the source code has been converted to GCC's intermediate representation but before any target-specific optimizations are done. Several optimization options are available to improve the accuracy of the fixed-point arithmetic, including affine range estimation, rounding, and double-precision multiplications. Fixed-point code produced by fxopt can be significantly more accurate than typical fixed-point implementations with comparable execution time and code size. In many cases the fixed-point code produced by fxopt provides accuracy comparable to single-precision floating-point arithmetic with a factor of 10 faster execution.

garith is a game similar in spirit to BSD's "arithmetic" or TuxMath. The game asks you to perform a simple arithmetic operation within a certain time frame. It improves your skills by stressing the operations you get more frequently wrong or that longer to answer. The statistics are saved/restored across games, so that each game is tuned for your current arithmetic abilities.

Voynex calculator is a Web browser application designed to evaluate mathematical and JavaScript expressions. The main difference between it and other calculators is that it is possible to enter the whole expression at once instead of entering it step by step. For example, it can evaluate expressions like, "sin(sqrt(PI/3)+sqrt(PI/5))+cos(PI/2+1)", "x=pow(4,5)+3; 3*x+log(x)", or "0xff07+0x1c04*(0x45+0x55>>1)". The power of the JavaScript language itself is used to evaluate expressions of arbitrary complexity. It offers a wide set of mathematical functions to calculate trigonometrical, logarithmic, and other expressions.

An Openbravo appliance that is easy to use and lightweight.