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 ...

If you are using Microsoft Excel to manage numerical data, at some point you're inevitably going to display percentages. Doing so can give you a new insight, or make summarizing heaps of data a bit ...

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 ...

The $130 fishing rod was first marked down 40 percent, and now it’s an additional 25 percent off. How much will it end up costing? If you’re not sure how to go about figuring this out, you’re not ...

Calculating how far a number has declined from one year to the next is pretty easy if you are only considering a one year period. You subtract the current year's number from last year's number, then ...

Employee labor percentage, more commonly called the cost of labor percentage, states the overall payroll expenditure for a business as a proportion of gross sales. Payroll is a major expense for any ...

How to calculate percentages is easier than you think. Quick, what’s 36% of 25? Or how about 250% of 20? Learn a quick and dirty tip to help you calculate all of those pesky percentages in your head.

Calculate annual % change by dividing start by end value, raising to inverse years, minus one, times 100. Ex: a drop from $15M to $10M over 2 years is a 18.4% average annual decline. This calculation ...