When is a time when you have used grade school or university math or science out of a class?

IRL? (In real life)? I wrongly used ! factorials when trying to determine my age (adjusted for time travel or epilepsy) . I used physics to get out of a fast flowing river that I fell in when I was 12. I went laterally instead of directly towards the shore. Sorta like the last ship in space invaders. You aim for where the ship would be and not directly towards the ship. Physics saved my life.