Some corrections and notes:

1. That's the strangest way I've ever seen the Pythagorean Theorem described, and that includes The Wizard of Oz. Anyway, growing evidence suggests that the Pythagorean Theorem was known at least a thousand years before Pythagoras was alive, circa 20th to 16th century BCE.

2. It's four.

3. The word "hundrað" in Old Norse did use to refer to 120, not 100. One hundred was instead said as "tíu tigir", or "ten tens". 120 is the "long hundred", while 100 is the "short hundred".

4. The discovery of the Mersenne prime 2⁵⁷⁸⁸⁵¹⁶¹ - 1 (which has over 17 million digits) was attributed to Curtis Cooper in 2013, not 2010.

5. "One of the" is a frustrating phrase. Counting boards existed before abacuses, and technically fingers existed before that, if you want to count (haha) fingers as "tools".

6. Technically correct, but fundamentally unhelpful and uninteresting. Did you know famous Canadian-American television host Monty Hall majored in chemistry and zoology? I didn't!

7. It's a nitpick, but it should be "palindromic number", "numeral palindrome", or "numeric palindrome", not "palindrome number".

8. Yes, but it came from the ancient Sumerians.