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HESI mathematics runs to about 50 questions, and it is deliberately practical. The exam is checking whether you can handle the arithmetic a nurse does on a shift, which means conversions, proportions and reading a problem carefully enough to know what is being asked.
What recurs
- Fractions, decimals and percentages, including converting between them and ordering them.
- Ratios and proportions. The single most useful skill in the section, because most conversion questions are proportions in disguise.
- Household and metric conversions. Teaspoons, tablespoons, ounces, cups, pints, quarts, millilitres, litres, grams, kilograms, pounds.
- Military time. Converting to and from the 24-hour clock, and adding intervals across midnight.
- Roman numerals, which still appear on prescriptions.
- Basic algebra. Solving for one unknown, no more than that.
Set it up the same way every time
Write the quantity you have, write the conversion as a fraction with the unit you want on top, multiply, and check that the unwanted unit cancels. It takes ten extra seconds and it is the difference between a correct answer and one that is off by a factor of a thousand.
The classic error is not arithmetic. It is answering in the wrong unit because the question asked for millilitres and the numbers were in litres. Underline the unit the answer must be in before you start.
Read the question twice, not the options
Distractors on this section are built from the predictable mistakes: the inverted ratio, the unconverted unit, the value before the last step. If your answer matches one of the options exactly, that is not evidence you are right. It is what a well-built distractor is for.
Practise under the clock
These questions are individually easy and collectively slow. A calculator is generally available for this section, which removes arithmetic risk and leaves setup as the whole test. Practise in blocks of 25 with a timer, because the failure mode here is running out of time on the last ten, not getting the maths wrong.
If conversions are your weak point, the TEAS article on the same topic covers the same ground with more worked examples: TEAS math formulas and conversions.