Overview
The Calculator is a fully functional four-operation calculator with full keyboard support, a two-line display showing both expression and result, thousands-separator formatting, scientific notation for large numbers, and a scrollable calculation history that lets you reload previous results.
How to Use
Click buttons or use your keyboard (0–9 for numbers, +−×÷ for operators, Enter or = for equals, Escape to clear, Backspace to delete). The expression line shows your ongoing calculation. After pressing equals, click any history item to reload its result. The AC button clears all, +/− toggles sign, and % converts to percentage. Supports chained operations.
Background & Context
The first mechanical calculators were developed in the 17th century by pioneers including Blaise Pascal (Pascaline, 1642) and Gottfried Wilhelm Leibniz. The first electronic calculator (ANITA) was introduced in 1961. Texas Instruments released the first handheld electronic calculator in 1967. Today’s smartphone calculators have more computing power than the computers that guided the Apollo moon missions.
