HESI A2 Math Formulas and Conversions to Review

Master fractions, decimals, and percentages

Practise moving between equivalent forms and estimating before calculating. To find a percentage of a number, convert the percentage to a decimal and multiply. To find percent change, divide the change by the original value before multiplying by 100.

• Add and subtract fractions using a common denominator

• Multiply fractions straight across, then simplify

• Divide by multiplying by the reciprocal

• Move between decimals, fractions, and percentages

Use proportions for ratios and rates

Write corresponding quantities in the same positions, include units, and solve the cross-products. Proportions are useful for scale, unit price, and dosage-style arithmetic, but always confirm that the requested unit matches your result.

• Part-to-part and part-to-whole ratios

• Unit rates

• Direct proportions

• Multi-step word problems

Review common measurement relationships

Learn the core metric prefixes and the household or time relationships specified by your study materials. Conversion factors should cancel unwanted units. Avoid relying on a conversion that your program or test materials define differently.

• 1 kilogram = 1,000 grams

• 1 gram = 1,000 milligrams

• 1 liter = 1,000 milliliters

• 1 hour = 60 minutes

• 1 day = 24 hours

Know essential geometry and algebra

For rectangles, area is length times width and perimeter is twice the sum of length and width. For triangles, area is one-half base times height. Practise isolating a variable and checking the solution in the original equation.

Use a reliable problem-solving sequence

Underline the requested quantity, list known values with units, estimate the likely range, choose the operation, and check whether the final unit and magnitude make sense. This routine catches more errors than rushing directly to calculator keys.