Glossary
exponent
An exponent states how many times a base is multiplied by itself, so 10³ means 10 × 10 × 10, and for a power of ten, each step moves the decimal point one place.
An exponent tells you how many times a base is multiplied by itself: 2⁴ is 2 × 2 × 2 × 2, and 10³ is a thousand. In this exam the base that matters is ten, because the metric system is built on powers of ten — each step up a prefix multiplies by 1,000 or 100 or 10, which is why converting between metric units is a decimal-point move rather than a calculation. Two rules prevent routine errors. An exponent applies only to the number directly beneath it, so −3² is −9 while (−3)² is 9. And a negative exponent is a reciprocal, not a negative number: 10⁻² is 0.01. When you convert, count the steps between the prefixes and move the point that many places in the direction of the unit you are converting to.
Taught in
Related terms
- order of operations — The order of operations is the fixed sequence for evaluating an expression: parentheses, exponents, multiplication and division left to right, then addition and subtraction left to right.
- metric prefix — A metric prefix names a power of ten applied to a base unit — kilo is 1,000, centi is one hundredth, milli is one thousandth — so converting between them moves the decimal point.
Source: The math guides in this course (ratio and proportion, measurement and conversion, dosage calculation): every definition and worked value above was written for this course, because arithmetic and unit conversion are not a publisher's prose, and each guide shows the method worked. Elsevier's own HESI A2 page, which names math among the areas the exam covers, is the exam-side source. (Elsevier HESI A2 page accessed 2026-10-23; definitions written 2026-10-27)