Sigma is a powerful but easy to use calculator. Includes advanced financial functions, scientific functions, calculation history, multiple tape / history files, and expression editing. Programming for repeated tasks, scenarios, and utilities. Every Day Ease of Use. Simple interface with history mode for expressions and calculations. Ability to use former expressions or values. Haptic feedback provides for a natural calculator feel. All Devices. All Modes. Support for light and dark on iPhone and iPad. Landscape support. Dynamic text size support. iCloud sync history, current calculation, programs, and variables across all devices. Multi-tasking on the iPad in portrait and landscape modes. Sync across iPhone, iPad, and soon MacOS. Financial Calculator. Time Value of Money (TVM) loan calculations with period, interest, present value, future value, and payment. Any four values can be set to compute the remaining variable. Enables easy to use what-if scenarios. Amortization allows computing compound interest, principle, and loan balance. Statistics with one or two variables, x,y predictions, 6 regression models, best-fit regression selection, standard deviation, aggregates, random value generation, permutations, and combinations. Cashflow analysis, bonds, interest conversions, margin / markup, breakeven analysis, and more. Multiple Tape Files Use multiple tape files to calculator totals, with sections and subtotals. Organize calculations into multiple files. Share and email files. iCloud Drive support sharing tape files across devices. Programmable Calculator. Create programs to repeat tasks, compare scenarios, and easily build conversion utilities. Support for variables, arrays, financial, scientific, and utility functions. Solver function for computations such as annual interest or rate of return. Bisect function for computations such as yield to maturity. Science and Utility. Trigonometric functions, decimal rounding, display rounding, date functions, roots, powers, and exponentials.