Into Math Grade 5, Unit 2: Add and Subtract Fractions
In this unit, your child learns to add and subtract fractions and mixed numbers with unlike denominators. They find a common denominator, rename each fraction as an equivalent fraction, and then combine. Story problems ask them to estimate with benchmarks like 1/2 and 1 to check their work. It leads straight into multiplying and dividing fractions in the next unit.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Unit 2?
- Finding a common denominator and renaming fractions and mixed numbers as equivalent fractions before adding or subtracting them. Learn more: Adding and subtracting fractions like 2/3 + 1/4
- Solving word problems with fractions of the same whole, and estimating with 0, 1/2, and 1 to check answers. 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
- Talk about time in fractions of an hour: if homework took 1/2 hour and reading took 1/4 hour, how long was that altogether? Use a clock face to check.
- Measure ingredients for a no-cook snack, like yogurt parfaits. Ask how much more 3/4 cup is than 1/3 cup, and how to rewrite both in twelfths.
- Ask 'about how much?' before solving any fraction problem together. Is 5/8 + 3/4 more or less than 1? A quick guess catches many mistakes.
Where kids can get stuck
- Adding numerators and denominators straight across, so 2/5 + 1/2 becomes 3/7, which is smaller than 1/2 by itself.
- Subtracting the smaller fraction from the larger, so 3 1/4 − 1 1/2 comes out as 2 1/4 instead of 1 3/4.
- Treating half of a small pizza and half of a large pizza as the same amount, mixing up different wholes.
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.
- common denominator
- A denominator that two or more fractions share, like 12 for 2/3 and 1/4.
- equivalent fractions
- Fractions that name the same amount, like 1/2 and 3/6.
- 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.
- whole
- The full amount, one complete thing or group, that a fraction is part of.
- estimate
- A close guess found by rounding or using easy numbers.
Want to help your child master fractions with unlike 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.
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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 Into Math Grade 5 Unit 2 cover?
Into Math Grade 5 Unit 2 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.