Bridges in Mathematics Grade 5, Unit 1: Expressions Equations & Volume
In this unit, your child starts fifth grade with two big ideas: writing and solving expressions with parentheses and brackets, and measuring volume, the space inside a box. They count cubes, then multiply length, width, and height. The careful step-by-step thinking from expressions carries into the next unit, adding and subtracting fractions with different denominators.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Unit 1?
- Evaluating expressions with parentheses and brackets by working the innermost group first, so 2 × (5 + 3) gives 16. Learn more: Solving number sentences with parentheses
- Writing a phrase like “add 8 and 7, then double it” as (8 + 7) × 2, and reading what an expression means. Learn more: Turning words into number sentences
- Understanding volume as the space inside a solid, measured in unit cubes packed with no gaps or overlaps. Learn more: Volume: how much space is inside a solid
- Counting unit cubes, including hidden ones, to find the volume of a box in cubic centimeters or cubic inches. Learn more: Finding volume by counting cubes
- Multiplying length × width × height to find a box's volume, and adding two boxes' volumes for a joined shape. Learn more: Finding the volume of a box
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
Work out (25 - 5) × 3.
- 10
- 70
- 60
How you can help
- Write 3 × (4 + 2) and 3 × 4 + 2 on a napkin at dinner. Ask your child to work out both, 18 and 14, and explain why the parentheses change the answer.
- Describe a snack order out loud, like 4 friends each getting a $2 juice and a $1 apple. Ask your child to write one expression, 4 × (2 + 1), then find the total of $12.
- Pick up a cereal or shoe box and ask how many 1-inch cubes might fill it. Measure the length, width, and height together, then multiply to check the guess.
Where kids can get stuck
- Working left to right past the parentheses, so 3 × (4 + 2) becomes 12 + 2 = 14 instead of 18.
- Writing the numbers in the order they are heard, so “double the sum of 8 and 7” becomes 2 × 8 + 7.
- Adding length, width, and height, so a 4 by 3 by 2 box gets a volume of 9 instead of 24.
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
- expression
- Numbers and operation signs written together to show a calculation, like 3 × (4 + 2).
- parentheses
- The curved symbols ( ) that tell you to do the math inside them first.
- brackets
- The square symbols [ ] that group part of an expression, often around parentheses.
- evaluate
- To work out the value of an expression.
- volume
- The amount of space inside a solid, measured in cubic units.
- unit cube
- A cube with each side 1 unit long, used to measure volume.
- cubic unit
- A cube with sides 1 unit long, used to measure volume.
- rectangular prism
- A box shape with six rectangle faces.
Ready to build your child’s confidence with expressions and volume?
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 1 cover?
Bridges in Mathematics Grade 5 Unit 1 covers these math standards. Each one links to what it means, sample questions, and teaching strategies.
- 5.OA.A.1: Solve problems with parentheses and brackets, working inside first.
- 5.OA.A.2: Turn words into calculations like (5 + 7) × 3, and explain them.
- 5.MD.C.3: Understand volume: how many cubes it takes to fill a solid shape.
- 5.MD.C.4: Find the volume of a shape by counting cubes.
- 5.MD.C.5: Find the volume of a box by multiplying its length, width, and height.
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.