You might get confused if you look up George Washington's birthday because it is listed as Feb 11, 1731 and Feb 22, 1732.
George was actually born on Feb 11, 1731, but in 1752 Great Britain (an it's colonies in the new world) switched over to the new Gregorian Calendar which skipped (or lost) 11 days.
George Washington started celebrating his birthday on Feb 22nd instead of the 11th because he was not actually a year older until the 11 lost days were added back in.
That's why we celebrate his birthday and President's Day on Feb 22nd.
You might also notice that Georges old birthday was listed as 1731 but his new birthday was listed as 1732. Well the official year in Great Britain (and their colonies in America) began on March 25th each year (it was known a Lady Day). After the calendar change they started the new year on January 1st. Before the calendar change the new year had not begun yet (so it was 1731), but after the calendar change the new year was counted as having begun on January 1st (so it was now 1732).
You might also enjoy this mathematical method of predicting the future.
First, I want you to think of a number - but not just any old number. I want you to think of your age. Don't say it out loud, I can read you mind just fine. Now add 5 to that number. Have you done that yet. OK.
That is how old you will be in 5 years!
(AMAZING - I KNOW WHAT YOUR ARE THINKING - HOW DID HE DO IT???)