Bridges in Mathematics Grade 5, Unit 2: Adding & Subtracting Fractions
In this unit, your child adds and subtracts fractions with unlike denominators, like 2/3 + 1/4, by renaming both with a common denominator first. Story problems ask whether each answer is reasonable. After the expressions and volume work, this unit focuses on fractions, which return in the next unit on place value and decimals, where tenths and hundredths are fractions too.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Unit 2?
- Renaming fractions with a common denominator, so 2/3 + 1/4 becomes 8/12 + 3/12 = 11/12, then adding or subtracting. Learn more: Adding and subtracting fractions like 2/3 + 1/4
- Solving story problems that add or subtract fractions, and checking each answer against benchmarks like 1/2 and 1. 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 one sheet of paper into thirds and another into fourths. Ask your child how to cut both into twelfths so the pieces match, then add 1/3 + 1/4 to get 7/12.
- Ask an estimate question at snack time: if you ate 1/2 of a sandwich and then 3/8 more, did you eat more or less than a whole? Then find the exact amount, 7/8.
- Measure ingredients together, like 3/4 cup of flour and 2/3 cup of oats. Ask your child how much more flour there is, 1/12 cup, and which common denominator they used.
Where kids can get stuck
- Adding the numerators and the denominators, so 1/2 + 1/3 becomes 2/5, which is less than 1/2.
- Changing the denominator without changing the numerator, so 2/3 becomes 2/12 instead of 8/12.
- Accepting an answer like 3/7 for 2/5 + 1/2, without noticing it must be more than 1/2.
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 of a fraction, which counts how many parts you have.
- denominator
- The bottom number of a fraction, which tells how many equal parts make a whole.
- common denominator
- The same bottom number shared by two fractions, so their parts are the same size.
- 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
- An easy fraction like 0, 1/2, or 1 used to estimate or compare.
- estimate
- A close guess found with easier numbers, used to check whether an answer makes sense.
Want to help your child master adding and subtracting 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 Bridges in Mathematics Grade 5 Unit 2 cover?
Bridges in Mathematics 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.