operations

This software can add or subtract days/months from a date, calculate days between two dates, and convert dates in several solar calendars including Gregorian, Julian, ISO 8601 Week, Hermetic Leap Week, and day-in-year (yyyy-ddd).

RekenTest is a free open-source software for improving arithmetic abilities. It provides comprehensive practice with various calculations such as decimals, money issues, fractions, and percentages. The software supports languages like English, Spanish, Portuguese, Dutch, and Turkish.

Smooth Operators is a comprehensive software for mastering the order of operations. It includes an interactive lesson, click-to-practice operands, and typing tests for practice. It prepares students for algebra and higher mathematics.