'''First order approximation''' (also 1<sup>st</sup> order) is the term [[scientists]] use for a further [[educated guess]] at an answer. Some simplifying assumptions are made, and when a number is needed, an answer with only one [[significant figure]] is often given. A first order approximation of a [[function]] (that is, mathematically determining a [[formula]] to fit multiple [[data point]]s) will be a straight [[line]] with a [[slope]]. For example,
