Scientific American presents Math Dude by Quick & Dirty Tips. Scientific American and Quick & Dirty Tips are both Macmillan companies. Long time math fans may remember our first foray into the world ...

Let's face it: Even the best budgets can't always predict your actual expenses. Things happen. Unexpected costs arise. That's life. That's why it's so useful to review your budget after a project is ...

Calculating profit as a percentage of revenue shows relative profitability, like Apple's 30.5% vs Fitbit's 20.5%. Common size income statements allow comparisons across companies and time by ...

Calculate average percentage difference by subtracting, then dividing price differences. Average percentage difference helps foresee market trends and irrational periods. Understanding this metric can ...

One way to find a percentage of an amount is to use 1%, 10% and 50% as building blocks. 1%, 10% and 50% can be used as building blocks for working out percentages in your head. 1% is 1⁄100. Work out 1 ...