i-Ready Classroom Mathematics Grade 5, Unit 3: Addition and Subtraction of Fractions
In this unit, your child adds and subtracts fractions and mixed numbers with unlike denominators. They use equivalent fractions to make the pieces the same size, model with number lines, and check answers by estimating. After a unit on whole numbers and decimals, it brings fractions to the center and prepares for multiplying and dividing them in the next unit.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Unit 3?
- Making same-size pieces with equivalent fractions, like 5/6 − 1/4 = 10/12 − 3/12 = 7/12, and doing the same with mixed numbers. Learn more: Adding and subtracting fractions like 2/3 + 1/4
- Modeling fraction word problems on number lines, and estimating to check that each answer is reasonable. Learn more: Story problems that add and subtract fractions
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
Which common denominator could you use to add 3/4 and 5/6?
- 10
- 12
- 6
How you can help
- Ask how much of a pizza is left if one person eats 1/4 and another eats 1/3. Let your child find the part eaten, 7/12, then the leftover, 5/12.
- Use a ruler marked in inches to add lengths like 2 3/8 and 1 1/2 inches. Ask your child to estimate first, then find 3 7/8 inches.
- Ask a quick check question before solving: is 5/6 − 1/4 more or less than 1/2? Let your child explain, then work out 7/12.
Where kids can get stuck
- Subtracting numerators and denominators, so 5/6 − 1/4 becomes 4/2 instead of 7/12.
- Finding a common denominator but forgetting to rename the numerator, so 1/4 becomes 1/12.
- Treating a part of one whole and a part of a different whole as the same amount.
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
- equivalent fractions
- Different-looking fractions with the same value, like 2/3 and 8/12.
- common denominator
- A denominator two fractions can both be renamed with, like 12 for 1/3 and 1/4.
- numerator
- In 3/4, the 3: the number of equal parts being counted.
- denominator
- In 3/4, the 4: the number of equal parts the whole is cut into.
- mixed number
- A number written as a whole number plus a fraction, like 3 3/4.
- number line
- A straight line marked with evenly spaced numbers, including fractions.
- estimate
- A close guess found with easier numbers, used to check whether an answer makes sense.
Want to help your child master fraction addition?
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.
Join the club
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 i-Ready Classroom Mathematics Grade 5 Unit 3 cover?
i-Ready Classroom Mathematics Grade 5 Unit 3 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.