The Danish word for 99 is nioghalvfems, which literally means "nine and half five." Which you could be forgiven for assuming meant 11½. The trick is that a) "half five" actually means 4½, as in half less than five, and b) it's implied that you're supposed to multiply the second part by 20. So the proper math is 9 + (-½ + 5) * 20 = 99.
As guy who hate French language and was learning in 1999 I can confirm it was pain to read the topic of lesson and the date. I was so happy when we switched to 2000.
Whole generations of French students that have no idea they escaped having to write "mille neuf cent quatre-vingt dix-neuf" over and over again, in cursive of course.
The British one has the "color" changed changed to "colour" due to British spelling of color.
The Spanish one has an upside down semi colon because in Spanish you write questions like this: ¿Is this an example question?
The French one is because the French number system makes absolutely no sense and to say 99 you have to say quatre-vingt-dix-neuf (meaning 4 x 20 + 19).
Joke aside, it's not taught as 4 × 20 +10 but simply “90 is pronounced quatre-vingt-dix” — which kinda is a mouthful, but you rarely count to 90 as a kid anyway.