Teacher Guide: Improper Fractions
Learn what improper fractions are, how they differ from proper fractions, and why they are equal to or greater than 1.
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Class quiz
10 questions on Fraction Basics. Students join with a name, you see everyone's score.
For Teachers
- Define an improper fraction as a fraction whose numerator is greater than or equal to its denominator
- Classify fractions as proper or improper by comparing numerator and denominator
- Decide whether a fraction is less than, equal to or greater than 1
- Locate improper fractions on a number line beyond 1
- Recognize improper fractions that are equal to whole numbers, like
- • What Are Fractions: numerator, denominator and equal parts
- • Equivalent Fractions: the same value written in different ways
- • Basic multiplication and division facts
- 1. Can you eat more slices than one pizza has? How would you write that as a fraction?
- 2. Why is equal to 1? Can you find three other fractions that are equal to 1?
- 3. Is more or less than 1? How do you know without calculating?
- 4. Why might someone write instead of saying one and three quarters?
A fraction is always less than 1
Remediation: Count unit fractions aloud past one whole: one quarter, two quarters, three quarters, four quarters, five quarters. Show the jumps continuing on a number line from 0 to 3.
A fraction whose numerator equals its denominator is proper
Remediation: Shade every part of a fraction bar: fills the whole bar. Proper fractions never fill the whole bar, so belongs with the improper fractions.
A bigger numerator always means a bigger fraction
Remediation: Compare and on the number line: is only one eighth past 1, while is one quarter past 1. Always look at the numerator and the denominator together.
For Struggling Students:
- • Use fraction strips or paper pizzas so students can physically build more than one whole
- • Work only with halves and quarters at first
- • Practice counting aloud past one whole: four quarters, five quarters, six quarters
For On-Level Students:
- • Classify mixed sets of proper and improper fractions
- • Place improper fractions with denominators 2, 3 and 4 on a number line from 0 to 3
- • Find improper fractions that are equal to whole numbers
For Advanced Students:
- • Compare improper fractions with different denominators, like and
- • Find all fractions with denominator 5 that lie between 2 and 3
- • Preview mixed numbers by splitting improper fractions into wholes and a remainder
- 3.NF.A.2.B (CCSS.MATH.CONTENT.3.NF.A.2.B)
Represent a fraction a/b on a number line diagram by marking off a lengths 1/b from 0
- 3.NF.A.3.C (CCSS.MATH.CONTENT.3.NF.A.3.C)
Express whole numbers as fractions, and recognize fractions that are equivalent to whole numbers
- 4.NF.B.3.B (CCSS.MATH.CONTENT.4.NF.B.3.B)
Decompose a fraction into a sum of fractions with the same denominator in more than one way
- visualFraction Number Line from 0 to 3
Students count quarter jumps past 1 and 2 and label the improper fractions
- activityPizza Slice Count
Groups combine paper pizza slices from several pizzas and name the total as an improper fraction
- worksheetLess Than, Equal to or More Than 1?
Sort fractions into three columns and mark each one on a number line
Lesson Content
Everything students see: definition, examples, common mistakes, applications. Tap to open.
Lesson Content
Everything students see: definition, examples, common mistakes, applications. Tap to open.
Definition
- Numerator smaller than the denominator: proper, less than 1 ()
- Numerator equal to the denominator: improper, exactly 1 ()
- Numerator greater than the denominator: improper, more than 1 ()
Worked Examples
Sort these fractions: , and . Which are proper and which are improper?
Look at
Numerator , denominator : → Proper, less than 1
Look at
Numerator , denominator : → Improper, more than 1
Look at
, so all five fifths together make one whole → Improper, exactly 1
Answer: is proper. and are improper, and .
Common Mistakes
Thinking a fraction can never be greater than 1
Why it's wrong: Fractions are often introduced as parts of one whole, so it seems impossible to have more parts than the whole has. But a fraction counts equal parts, and you can count more parts than fit into one whole.
Correct: means seven quarters: one whole (four quarters) plus three more quarters, so .
Calling a proper fraction
Why it's wrong: It looks like an ordinary fraction, but a proper fraction must be less than 1, and is exactly 1.
Correct: When the numerator equals the denominator, the fraction is improper and equal to 1: .
Putting between 0 and 1 on the number line
Why it's wrong: Many students stop counting quarters at 1. But after the jumps simply keep going, and is the next mark.
Correct: Keep counting past 1: , so is one quarter to the right of 1.
Thinking improper means wrong
Why it's wrong: In everyday language improper sounds like a mistake, but in math it is only the name for fractions that are 1 or more.
Correct: is a perfectly correct answer. Often it is the most useful form for calculating.
Why It Matters
- Cooking: Six quarter cups of flour are cups, more than one cup
- Time: Five quarter hours are of an hour, which is 75 minutes
- Sharing food: Eating 9 slices from pizzas cut into 8 slices each means eating of a pizza
- Adding fractions: , so answers often come out improper
Real World Applications
Cooking with Measuring Scoops
Recipes are often measured with small scoops, and several scoops easily add up to more than one cup.
Example:
Three scoops of cup of milk are cups, which is more than 1 cup.
Your only measuring scoop holds cup. A pancake recipe needs 6 scoops of flour.
How many cups of flour is that, written as a fraction?
Step 1: Write the mathematical expression
Count the quarter cups:
Time in Quarter Hours
A quarter hour is 15 minutes, so timetables and schedules often count time in quarters of an hour.
Example:
A film that lasts 6 quarter hours lasts of an hour, which is 90 minutes.
Swimming practice lasts 5 quarter hours.
What fraction of an hour is that, and how many minutes?
Step 1: Write the mathematical expression
Five quarter hours of 15 minutes each:
Water Bottles for a Team
Drinks are often sold in half liter bottles, and a few bottles quickly add up to several liters.
Example:
Two half liter bottles hold liter of water.
A football team brings 7 bottles, each holding liter of water.
How many liters of water is that, written as a fraction?
Step 1: Write the mathematical expression
Count the half liters:
Key Takeaways
- 1An improper fraction has a numerator greater than or equal to its denominator, like or
- 2A proper fraction has a smaller numerator than denominator and is always less than 1
- 3If the numerator equals the denominator, the fraction is exactly 1:
- 4If the numerator is greater, the fraction is more than 1 and lies to the right of 1 on the number line
- 5If the numerator is a multiple of the denominator, the fraction is a whole number:
- 6Improper is only a name, not a mistake. can also be written as the mixed number , which comes in the next lessons
Frequently Asked Questions
Is a proper or an improper fraction?
Why are they called improper?
Can every whole number be written as an improper fraction?
Do I always have to change an improper fraction into a mixed number?
Glossary
- Proper fraction
- A fraction whose numerator is smaller than its denominator, like . It is always less than 1.
- Improper fraction
- A fraction whose numerator is greater than or equal to its denominator, like or . It is 1 or more.
- Numerator
- The top number of a fraction; it counts how many equal parts there are
- Denominator
- The bottom number of a fraction; it tells how many equal parts make one whole
- Whole number
- One of the numbers 0, 1, 2, 3 and so on. Some improper fractions are whole numbers, like .
- Mixed number
- A whole number and a proper fraction written together, like . It is another way to write an improper fraction.
Formula Card
Proper fraction
The numerator is smaller than the denominator
Equal to one
The numerator equals the denominator, so the fraction is improper and equal to 1
Greater than one
The numerator is greater than the denominator, so the fraction is improper
Whole number
If $b$ divides $a$ exactly, the fraction is a whole number, for example $\frac{12}{4} = 3$