TEAS Calculation Playbook: Formulas and Conversions That Turn Word Problems Into Points

ATI TEAS calculations are not about hard math.

They are about setup and units.

The TEAS Math section has 38 questions in 57 minutes, and it covers two main areas: Numbers and Algebra and Measurement and Data. A four-function calculator is provided, but the calculator cannot decide which formula to use. It cannot tell you whether the answer should be in mL, cm², percent, dollars per hour, or cubic units.

That part is your job.

The best TEAS math strategy is simple:

Translate. Set up. Calculate. Check units.

Before You Calculate

Most TEAS math mistakes happen before the arithmetic starts.

Students often know how to multiply, divide, or convert, but they lose points because they:

• Misread what was given

• Missed what was being asked

• Used the wrong unit

• Skipped a conversion

• Used total instead of part

• Rounded too early

Before touching the calculator, slow down and follow three steps.

1. Translate The Wording

First, identify:

• What is given?

• What is asked?

Underline or write down the key numbers and labels.

For example, if a word problem gives total cost, number of items, and time, decide which numbers matter for the question. Do not assume every number must be used.

Ask:

“What answer unit do I need?”

That question keeps the setup focused.

2. Choose The Setup

Next, decide what kind of problem it is.

Common TEAS math setups include:

• Ratio

• Percent

• Proportion

• Equation

• Geometry

• Rate

• Data interpretation

• Unit conversion

This matters because the same numbers can lead to different answers depending on the setup.

A percent problem is not solved the same way as a rate problem. A square-unit area problem is not the same as a cubic-unit volume problem.

3. Check The Unit

Before calculating, check the final unit.

Look for:

• mL

• cm

• cm²

• cm³

• percent

• per hour

• per minute

• grams

• kilograms

• dollars

• degrees

Units tell you what the math should do.

If the question asks for area, your answer should be in square units. If it asks for volume, your answer should be in cubic units. If it asks for a rate, your answer should include “per.”

Ratio And Percent Setups

Ratios, percents, and rates are high-value TEAS math skills because they appear in everyday word problems, data questions, and measurement contexts.

Proportion

A proportion compares two equal ratios.

A common setup is:

part / whole = part / whole

Use a proportion when two rates or relationships should match.

Example:

If 3 out of 5 students passed, how many would pass out of 40?

3 / 5 = x / 40

Cross-multiply or solve:

5x = 120

x = 24

The key is keeping matching units in matching positions.

Do not put part over whole on one side and whole over part on the other.

Percent Change

Use:

percent change = change / original × 100

First find the change:

new - original = change

Example:

A value increases from 100 to 115.

Change:

115 - 100 = 15

Percent change:

15 / 100 × 100 = 15%

The trap is using the new value as the denominator. Percent change is based on the original value unless the question says otherwise.

Ask:

“New compared to old? What was the original?”

Rate

Use:

rate = amount / time

Rate clues include:

• per hour

• per minute

• miles per hour

• mL per hour

• dollars per item

• words per minute

• flow

• speed

• dosage wording

Example:

If a person walks 12 miles in 3 hours:

12 / 3 = 4 miles per hour

The unit “per” tells you division is involved.

Conversions And Geometry

TEAS math includes measurement and data, so conversions and geometry deserve steady practice.

Metric Moves

Know the metric direction:

kilo → base → milli → micro

Common examples:

• 1 kg = 1,000 g

• 1 g = 1,000 mg

• 1 mg = 1,000 mcg

• 1 L = 1,000 mL

• 1 m = 100 cm

The rule is:

Move decimals only after naming the units.

Do not move a decimal because the number “looks right.” Name the starting unit, name the ending unit, then convert.

Area Vs. Volume

Area uses square units.

Volume uses cubic units.

That means:

• Area: cm², in², ft²

• Volume: cm³, in³, ft³, mL, L

If the unit changes from cm² to cm³, the setup changed.

Area measures surface.

Volume measures space inside.

A rectangle area problem is not the same as a box volume problem.

Common Geometry

Know the most common formulas:

• Rectangle area: A = l × w

• Triangle area: A = 1/2 bh

• Circle area: A = pi r²

• Circumference: C = 2 pi r

Watch for diameter vs. radius.

If the problem gives diameter, divide by 2 to get radius before using circle area or circumference formulas that require r.

Example:

Diameter = 10

Radius = 5

Circle area:

A = pi(5²) = 25pi

Data And Science Calculations

TEAS math and science-style calculations often overlap through data, measurement, and interpretation.

Mean

Mean means average.

Use:

mean = sum of values / number of values

Example:

Data set: 8, 12, 10, 6, 9, 11, 7, 10

Sum:

73

Number of values:

8

Mean:

73 / 8 = 9.125

Important trap:

Do not average percentages from different group sizes unless the groups are the same size.

If group sizes differ, you need a weighted average.

Density

Use:

D = m / V

Density equals mass divided by volume.

Example:

Mass = 30 g
Volume = 10 mL

D = 30 / 10 = 3 g/mL

Use the units to know what goes on top.

If the answer unit is g/mL, grams go on top and mL goes on bottom.

Scientific Notation

Scientific notation writes large or small numbers using powers of 10.

Example:

4.56 × 10³ = 4,560

A positive exponent makes the number bigger.

A negative exponent makes the number smaller.

Quick rule:

• Positive exponent: move decimal right

• Negative exponent: move decimal left

The exponent tells you how many places to move.

Point-Losing Traps

Watch for these common TEAS calculation traps:

• Wrong unit

• Skipped conversion

• Used total instead of part

• Used part instead of whole

• Rounded too early

• Confused area and volume

• Used diameter instead of radius

• Averaged percentages incorrectly

• Solved for the wrong value

• Did not check the final unit

A strong habit is to write the final unit before you calculate.

If the question asks for mL/hr, write:

Answer = ___ mL/hr

Then solve into that unit.

Use The TestFinesse Practice Loop

The TestFinesse method is:

1. Answer

2. Explain

3. Reveal

4. Fix the gap

For TEAS calculations, ask after every miss:

• Was this a setup mistake?

• Was this a formula mistake?

• Was this a unit mistake?

• Did I round too early?

• Did I answer the wrong thing?

Then write one rule for next time.

Example:

Next time, identify whether the question asks for area or volume before choosing the formula.

Final Takeaway

TEAS math is not about doing complicated calculations.

It is about setting up simple calculations correctly.

Focus on:

• Ratios

• Percents

• Rates

• Metric conversions

• Area and volume

• Geometry formulas

• Mean

• Density

• Scientific notation

• Unit checking

Use the calculator.

But memorize the setup.

Translate → set up → calculate → check units.

Accuracy sources checked: ATI TEAS Exam Details, ATI TEAS Sections and Timing, ATI TEAS Overview and Content Specifications, and ATI Calculator Policy.