Go Math! Grade 5, Chapter 11: Geometry and Volume
In this unit, your child ends the year with shapes and solids. They classify triangles and quadrilaterals by their sides and angles, sort them into a family tree, and find volume by counting unit cubes and by multiplying length × width × height, including figures made of two boxes. After converting units of measure, it is a chance to use multiplication in three dimensions.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Chapter 11?
- Defining volume as the space a solid takes up, measured in cubic units with no gaps or overlaps. Learn more: Volume: how much space is inside a solid
- Counting unit cubes to measure volume, including cubes hidden behind or under others, and naming cubic units. Learn more: Finding volume by counting cubes
- Using length × width × height to find volume, and adding the volumes of two rectangular prisms joined together. Learn more: Finding the volume of a box
- Explaining that properties of a larger group, like four right angles for rectangles, also belong to every square. Learn more: Why a square is also a rectangle
- Classifying triangles and quadrilaterals by sides and angles, and placing quadrilaterals in a family tree. Learn more: Sorting four-sided shapes into a family tree
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
Hana stacks 12 unit cubes into a tall tower. Then she takes it apart and uses all 12 cubes to build a long, low wall. How does the volume of the wall compare with the volume of the tower?
- They have the same volume
- The tower has more volume
- The wall has more volume
How you can help
- Sort the triangles and four-sided shapes you see on a walk or ride, like signs and windows. Ask your child to name each one by its sides and angles.
- Find the volume of a shoebox together: measure in inches, multiply length × width × height, and ask how many 1-inch cubes would fit inside.
- Build an L shape from two stacks of blocks. Ask your child to find each stack's volume, then add them for the whole shape.
Where kids can get stuck
- Confusing volume with area, counting the squares on one face of a box instead of the cubes inside.
- Naming a shape by how it is turned, calling a tilted square a “diamond.”
- Thinking a rhombus needs right angles, or that a rectangle needs four equal sides.
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
- volume
- How much space a 3-D shape takes up or holds.
- cubic unit
- A cube with sides 1 unit long, used to measure volume.
- rectangular prism
- A box shape with six rectangle faces.
- quadrilateral
- Any flat shape with four straight sides.
- parallelogram
- A four-sided shape with two pairs of parallel sides.
- rhombus
- A parallelogram with four equal sides, which may or may not have right angles.
- right angle
- A square corner, like the corner of a sheet of paper.
- equilateral triangle
- A triangle with three sides of equal length.
Want to help your child master geometry 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.
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 Go Math! Grade 5 Chapter 11 cover?
Go Math! Grade 5 Chapter 11 covers these math standards. Each one links to what it means, sample questions, and teaching strategies.
- 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.
- 5.G.B.3: Know that a square has everything a rectangle has, because it is one.
- 5.G.B.4: Sort shapes into families by their sides and angles.
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.