Calculus is useful to know, to understand the rates of change and how nature works.But it’s more important to understand the principles of calculus—where you’re measuring the change in small discrete or small continuous events.It’s not important you solve integrals or do derivations on demand, because you’re not going to need to in the business world.Least understood, but the most important principle for anyone claiming “science” on their side—falsifiability.If it doesn’t make falsifiable predictions, it’s not science.For you to believe something is true, it should have predictive power, and it must be falsifiable.I think macroeconomics, because it doesn’t make falsifiable predictions (which is the hallmark of science), has become corrupted.You never have a counterexample when studying the economy.You can never take the US economy and run two different experiments at the same time.