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 ...

Will Kenton is an expert on the economy and investing laws and regulations. He previously held senior editorial roles at Investopedia and Kapitall Wire and holds a MA in Economics from The New School ...

Percentages are a way of expressing proportion. Proportion tells you how much of one thing there is in relation to the whole. 'Per cent' means ‘out of 100’ and a percentage is written as a number with ...

Excel percentage formulas can get you through problems large and small every day—from determining sales tax (and tips) to calculating increases and decreases. We’ll walk through several examples below ...

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

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 ...