LeoCalculator is an application for performing calculation of mathematical expressions that could include not only basic operations but also functions and brackets. Edit box "expression" has to contain a string of mathematical expression that is supposed to be calculated. It can contain: numbers in with or without decimal point and with or without a power of 10 like 1.2e-2 or 3.E3 pi in this application is equal to 3.141592653 basic mathematical operations +-*/ power of grade operation ^ used like 2^3 = 8 brackets determining order of operation execution elementary mathematical functions: sincostanasinacosatanlnlog10exppow10abssqrt basic statistical functions as sum mean sigma (standard deviation) student and trust for calculation probability and trust interval. Arguments of the functions have to be an expression surrounded brackets Variables can be declared and edited separately from formula and can be any combinations of letters and numbers without spaces and reserved words: value expressions as usual are numbers but in most cases it could be mathematical expressions too.