Free ATI TEAS 7 Mathematics guide

October 2026 - Converting Fractions into Decimals Study Guide

Divide the numerator by the denominator. That is the whole method — but knowing the common conversions on sight saves time you will need on the harder questions, and it is the difference between answering a comparison question in five seconds and in forty.

Mathematics guide Numbers and algebra · 18 scored questions 5 min read

The method, and when to skip it

A fraction is a division waiting to happen: 3/8 means 3 divided by 8, which is 0.375. With a calculator provided, this is a keystroke — but you will not always want to reach for it, because a question that asks you to order five values is five divisions if you do not know the common ones.

Going the other way is easier still. Read the last decimal place to get the denominator: 0.45 ends in the hundredths, so it is 45/100, which simplifies to 9/20.

The conversions worth knowing on sight

These cover the overwhelming majority of what appears on the exam.

FractionDecimalPercentage
1/2 0.5 50%
1/3 0.333… 33.3%
2/3 0.666… 66.7%
1/4 0.25 25%
3/4 0.75 75%
1/5 0.2 20%
1/8 0.125 12.5%
3/8 0.375 37.5%
1/10 0.1 10%
1/100 0.01 1%

Building on what you know

You do not need to memorise every fraction — the multiples come free once you know the unit fraction.

  • Know 1/8 = 0.125, and 5/8 is five of them: 0.625.
  • Know 1/5 = 0.2, and 3/5 is 0.6.
  • Anything over 10, 100 or 1000 needs no division at all — just move the point.
  • A denominator that divides into 100 is easy: 7/20 is 35/100, so 0.35.

Thirds and sixths repeat and never terminate. If a question wants 2/3 as a decimal to two places the answer is 0.67, rounded — an answer choice of 0.66 is testing whether you truncated instead of rounding.

Ordering a mixed set

Worked example

Order from least to greatest: 0.6, 5/8, 62%, 3/5.

  1. Put everything in one form. Decimals are easiest here.
  2. 5/8 = 0.625. 62% = 0.62. 3/5 = 0.6.
  3. Now the set reads 0.6, 0.625, 0.62, 0.6.
  4. Order them: 0.6 and 3/5 are equal, then 0.62, then 0.625.

0.6 = 3/5, then 62%, then 5/8. Converting everything to one form before comparing is the only reliable way through a mixed set.

Terms to know

Terminating decimal
A decimal that ends, such as 0.375.
Repeating decimal
A decimal with a digit or block that repeats forever, such as 0.333….
Place value
What each digit is worth by position: tenths, hundredths, thousandths.
Rounding
Adjusting to a given number of places, looking at the next digit to decide.
Truncating
Cutting a decimal short without rounding. A source of wrong answers, not a method.

What the TEAS asks most

The same core ideas appear in different wording. If you can answer these without stopping to think, you have what this section requires.

Express this fraction as a decimal.

Numerator divided by denominator, rounded to whatever the choices show.

Express this decimal as a fraction in simplest form.

Read the last place for the denominator, then simplify.

Order this mixed list of fractions, decimals and percentages.

Convert everything to one form first — decimals are usually quickest.

Which of these is equivalent to the given value?

Convert the given value once, then test the choices against it.

Key points

  • A fraction is a division: numerator ÷ denominator.
  • To go from decimal to fraction, read the last place value as the denominator, then simplify.
  • Memorise halves, thirds, quarters, fifths, eighths and tenths.
  • Multiples come free: knowing 1/8 gives you 3/8, 5/8 and 7/8.
  • Round rather than truncate, and convert a mixed list to one form before comparing.

Review quiz

4 questions on this topic, each with the reasoning worked through. Pick an answer to see how it went, or open the explanation straight away.

  1. Question 1 of 4

    What is 7/8 as a decimal?

    Answer choices for question 1

    Show the answer and explanation

    Correct answer: B. 0.875

    7 divided by 8 is 0.875, or seven lots of 0.125. 0.78 is the digits of the fraction read straight off, 0.87 is 0.875 truncated rather than rounded, and 1.142 is 8 divided by 7 — the division done the wrong way round.

  2. Question 2 of 4

    Express 0.024 as a fraction in simplest form.

    Answer choices for question 2

    Show the answer and explanation

    Correct answer: B. 3/125

    The last digit is in the thousandths, so the fraction is 24/1000, and dividing both parts by 8 gives 3/125. 24/1000 is correct but unsimplified, while 24/100 and 12/50 both equal 0.24 — ten times too large, from misreading the place value.

  3. Question 3 of 4

    Which list is in order from least to greatest?

    Answer choices for question 3

    Show the answer and explanation

    Correct answer: B. 0.3, 1/3, 35%, 3/8

    As decimals these are 0.3, 0.333, 0.35 and 0.375, which is the order in the second choice. The first places 1/3 below 0.3, and the third places 35% below 1/3; the fourth is the correct order reversed.

  4. Question 4 of 4

    A dose is recorded as 0.4 of a tablet. Which fraction is equivalent?

    Answer choices for question 4

    Show the answer and explanation

    Correct answer: B. 2/5

    0.4 is 4/10, which simplifies to 2/5. 1/4 is 0.25, a frequent confusion because both contain a 4; 4/100 is 0.04; and 1/40 is 0.025. Only one choice actually divides out to 0.4.

Put this TEAS topic into practice

Build a set on converting fractions into decimals and use the rationale on every question to reinforce what you just reviewed.