If it isn't useful, why would they teach it to us?

I tried this on my maths professor and asked him to name three things that you use everyday. He said toothbrush, jacket, and water bottle. I then said “notice how you didn’t say algebra?”
AITA?

lol

I would like school better if useful information was mandatory, but "useless" subjects were optional. But the useless stuff may be for working or something, idk.