This provides calculators for dates, times, numbers, computer figures and Roman numerals. The date calculator lets you add and subtract dates. You can also convert to Julian Day Number. Reveal the moon phases and see equivalent dates in Jewish, Islamic and Julian calendars. Add and subtract time with the time calculator, which contains thousands of cities in a built-in database. If your city isn t already listed, you can add it. The numeric calculator is a standard calculator with trigonometry functions.