re: What's the highest level of Math you use regularly?

Counting aloud on my fingers or while pointing to days on a calendar. I don’t trust head-arithmetic or even date-calculation sites and apps.

Lawyer.

I will use a fancy interest calculator or brave the sum function in Excel.

I think that’s about the sum of it. My dad is a PhD polymer chemist. Skips a generation, I hear. He’s a step function ahead of me in maths.