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 ...

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.

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 ...

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 ...

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 ...

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 ...

It is possible to look at the difference between two numbers and work out the percentage increase or the percentage decrease. This is known as percentage change. Often goods are bought for one price ...