They told us that for nursing school then it was all middle school level ratio and proportion (admittedly with multiple ratio steps like when you've ratioed the right volume of the dose but then you need to convert that to the gtt of your drip kit). The only real equations needed were three (maybe I'm forgetting one) that you could just memorize for the week then forget again until next semester. Two were °F to °C / °C to °F with one inverted ratio +/- the constant. The other one was BSA with two variables but you don't have to solve for one or the other they're both just measurements you get from the patient and plug in.

...but then you realize that the only acceptable score on that test is a 100% (some programs will drop you if you get anything less than a 100% on the drug dose test after two tries) and that what nursing school is actually looking for is both accuracy and precision. You're doing a relatively basic but fundamentally logical, and more importantly highly repetitive puzzle 25 times in a row in an hour and if you make even one error you fail. I had to create a whole specific mental technique to beat my ADHD into submission enough to 100% that test (honestly half of what nursing school taught me was ultimately ADHD / attention management techniques, which it turns out is actually also most of being a nurse). Like the EMR does basically all of the math these days but being aware of where my attention is and why and how to nudge it where it needs to be has been suuuper useful.

Edit: BMI! That was the equation I was forgetting about. Weirdly it's mostly useful in population health but also if you're under a certain BMI on admission the EMR starts suggesting a diet consult every time I open that chart until I either document a reason to permanently override it or just put in the consult so that the dietician can immediately decide whether or not to start loading them full of protein shakes. Really important for the seniors if they go into the hospital with 0 chub they're probably not coming back out alive.