*Posted on on May 1, 2009*

From Zero to Hero

(This is one of a series of GMAT tips that we offer on our blog.)

The number 0 is a tricky one on the GMAT, as its unique properties are often either the key to unlocking a difficult solution, or the trap in to which a seemingly logical solution can lead you. Learning the properties of zero (keep in mind that it is an even number) is an important skill, particularly on data sufficiency problems. Even more importantly, never forget to consider zero as a potential value for a variable, as it often produces surprising results. Consider the case of zero as an exponent:

x^0 is, by definition, equal to 1. This concept may have bothered you in high school, as it seems almost arbitrary that an exponent without value would automatically lead to a value of 1. But noting the properties of exponents can help you to prove and more easily embrace and remember this useful device: take, for example, the expression x^2 * x^-2. You could rearrange this two ways: