Zearn Math Grade 5, Mission 3: Addition and Subtraction of Fractions
In this unit, your child adds and subtracts fractions with unlike denominators by making like units, rewriting 1/2 + 1/3 as 3/6 + 2/6. They work with mixed numbers, use number lines and area models, and solve word problems, estimating to check reasonableness. It follows the multi-digit operations unit and leads into multiplying and dividing fractions and decimals.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Mission 3?
- Making like units by renaming fractions as equivalent fractions, like 1/2 + 1/3 as 3/6 + 2/6, before adding or subtracting. Learn more: Adding and subtracting fractions like 2/3 + 1/4
- Solving word problems with fractions and mixed numbers, and estimating with benchmarks to decide whether answers make sense. 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
- Fold a sheet of paper in halves and then in thirds to show sixths. Ask your child to shade 1/2 and 1/3 and find how much is shaded together.
- Talk through a day in fractions of an hour, like 3/4 hour at practice and 1/3 hour of reading. Ask how much longer practice took.
- Ask your child to estimate a sum with benchmarks before solving, like 7/8 + 4/9. Is it more or less than 1? How can they tell?
Where kids can get stuck
- Adding numerators and denominators, so 1/4 + 2/3 comes out as 3/7, which is less than 2/3 alone.
- Renaming the denominators but not the numerators, so 1/2 + 1/3 turns into 1/6 + 1/6.
- Getting stuck on 1/3 − 2/3 in 4 1/3 − 2 2/3, instead of regrouping one whole as 3/3.
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
- numerator
- The top number in a fraction, telling how many parts you have.
- denominator
- The bottom number in a fraction, telling how many equal parts make a whole.
- like units
- Fractions with the same denominator, like 3/6 and 2/6, which can be added directly.
- equivalent fractions
- Fractions that name the same amount, like 1/2 and 3/6.
- common denominator
- A denominator that two or more fractions share, like 12 for 2/3 and 1/4.
- mixed number
- A whole number and a fraction together, like 2 1/2.
- benchmark fraction
- A familiar fraction, like 1/2, used to estimate or compare.
- number line
- A line with evenly spaced numbers, used to show and compare values.
Want to help your child master fractions with different denominators?
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 Zearn Math Grade 5 Mission 3 cover?
Zearn Math Grade 5 Mission 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.