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 ...

There are many situations in investing in which it makes sense to look at how two different numbers related to each other over time. Whether you're talking about two stocks in the same industry, the ...

Investopedia contributors come from a range of backgrounds, and over 25 years there have been thousands of expert writers and editors who have contributed. Robert Kelly is managing director of XTS ...

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 ...

An amount can be increased or decreased by a certain percentage to change its size. A reverse percentage problem involves finding the original amount before a percentage increase or decrease. The ...

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 ...

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 ...

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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 ...