Glossary
rounding
Rounding replaces a number with a near one at a chosen place value, using the digit after it: five or more rounds up, less than five rounds down.
Rounding replaces a number with a nearby one at a stated place value, usually fewer decimal places than the calculation produced. Look at the first digit being dropped: five or more, and the digit kept goes up by one; four or less, and it stays. Drop everything after that digit. Two cautions do real work on the exam. Carry the unrounded value through every intermediate step and round only at the end, because rounding early compounds the error — this is why a hand calculation and a calculator disagree in the last digit. And the number of places to keep comes from the question or the measuring instrument, not from habit: a value read off a syringe is not reported to four decimal places, and an answer choice that is rounded more coarsely than the others is often the one the problem's precision allows.
Taught in
Related terms
- decimal — A decimal writes a fraction using place value after a decimal point, so 0.75 means 75 hundredths, and the alignment of that point governs every operation.
- percent change — Percent change measures a change against the starting value: the amount of change divided by the original, then written as a percent.
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)