Lesson · M.4.2

Percentages and the Percent Formula

Convert cleanly between decimals, fractions and percents, then use the part over whole equals percent over 100 formula to solve any percent question on the HESI A2.

ObjectiveM.4.2Read4 minExam weightRatios, Proportions and Percentages ≈ 12% of Mathematics

This lesson is part of the full Study Guide

Unlock every lesson, unit, and quiz across every subject. The Mathematics ratios, proportions and percentages unit is included.

See editions and pricing →

What you will be able to do

Convert any decimal or fraction to a percent, and any percent back to a decimal, without a calculator.
Set up the percent formula correctly for all three question types: find the part, find the whole, or find the percent.
Spot which quantity is the whole in a word problem, even when the number 100 never appears.

What the lesson concludes

Percent means per hundred, so converting a decimal to a percent is just a two place shift of the decimal point.
The percent formula is part over whole equals percent over 100, and it solves all three percent question types.
The word of almost always marks the whole in a word problem.
Cross multiply, then divide by the one number left standing alone.
Round only at the end, and only when the exam or the situation actually calls for it.