Illustrative Mathematics Grade 3, Unit 5: Fractions as Numbers
In this unit, your child learns that fractions are numbers. They split shapes and strips into equal parts, name unit fractions like 1/8, build other fractions from them, place fractions on number lines, and compare fractions to find which are equal or larger. The next unit uses fractions to measure lengths to the nearest half and quarter inch.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Unit 5?
- Using fraction strips to see 5/8 as 5 parts of size 1/8, where the denominator, the bottom number, names the part size. Learn more: What a fraction like 3/4 means
- Partitioning number lines into equal lengths and placing fractions, including those greater than 1 like 7/4. Learn more: Fractions on a number line
- Explaining why 1/2 = 2/4 = 4/8 with strips and number lines, and comparing fractions like 3/4 and 3/6. Learn more about finding equal fractions, like 1/2 = 2/4: Finding equal fractions, like 1/2 = 2/4 · Learn more about comparing fractions by size
- Splitting shapes into equal parts in different ways, and showing why each piece is the same fraction. Learn more: Splitting shapes into equal parts
Sample questions to try together
These are real questions from our practice. Tap the speaker to hear one read aloud, or the light bulb for a hint, and talk about the answer together.
Question 1 of 3
Tariq is painting this paper strip blue for a class banner. So far he has painted the blue parts. What fraction of the strip does he still need to paint?
- 5/3
- 3/8
- 5/8
How you can help
- Fold three same-size paper strips into halves, fourths, and eighths, and line them up to find the fractions that match 1/2.
- Use a measuring tape or ruler to find 1/2, 1/4, and 3/4 of an inch, and talk about fractions as points on a line.
- Break a sheet of crackers or a granola bar into eighths, then ask how many eighths make one half (4).
Where kids can get stuck
- Thinking a fraction like 7/4 cannot exist because the top number is bigger than the bottom.
- Judging 3/6 bigger than 3/4 because 6 is bigger than 4.
- Folding strips into unequal parts and still labeling each part as an eighth.
Practice makes perfect
Bobby's Math Club has practice problems that adapt to your child’s level, each with a detailed explanation and an easy-to-follow video, so your child can build confidence in these skills one step at a time.
Words your child will hear
- fraction
- A number that shows part of a whole or part of a group.
- unit fraction
- A fraction for one equal part, like 1/3 or 1/8.
- numerator
- The top number in a fraction, counting the parts we are talking about.
- denominator
- The bottom number in a fraction, naming how many equal parts the whole has.
- number line
- A line with numbers placed in order at equal spaces.
- equivalent fractions
- Fractions that name the same amount, like 1/2 and 2/4.
- fraction strip
- A paper strip folded or marked into equal parts to show fractions.
- partition
- To split a shape or a line into equal parts.
Want to help your child master making sense of fractions?
In Bobby's Math Club, your child practices these skills at just the right level, with a hint when they need one, a clear explanation after every question, and kid-friendly videos. Unlimited practice is free.
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Written by Robert “Bobby” Barnett
Bobby is an award-winning math teacher, the author of Meet Every Learner’s Needs, and the father of two elementary-school math learners. He uses Bobby’s Math Club with his own kids a few times every week. Learn more or contact Bobby.
Which math standards does Illustrative Mathematics Grade 3 Unit 5 cover?
Illustrative Mathematics Grade 3 Unit 5 covers these math standards. Each one links to what it means, sample questions, and teaching strategies.
For teachers: Unit names and order vary between editions and districts, so your school’s own materials have the exact sequence. Learn how Bobby's Math Club can help your students grow.