Reveal Math Grade 3, Unit 7: Shapes and Perimeter
In this unit, your child sorts shapes by their attributes, or features, and sees that squares, rectangles, and rhombuses all belong to the larger family of quadrilaterals. Children also find perimeter, the distance around a shape, and missing side lengths. It follows the fractions unit, links back to the earlier area work, and leads into a unit on data and graphs.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Unit 7?
- Sorting shapes by attributes, like the number of sides and square corners, and naming quadrilaterals such as rhombuses, rectangles, and squares. Learn more: Sorting four-sided shapes into families
- Finding perimeter by adding side lengths, solving for a missing side, and seeing that rectangles with equal perimeters can have different areas. Learn more: Perimeter: the distance around a shape
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
Look at the shapes. They are all quadrilaterals. How many of them have 4 square corners?
- 2
- 3
- 1
How you can help
- Walk around a table or rug, counting steps along each side, then add the sides together to find its perimeter in steps.
- Make shapes with straws or pipe cleaners and ask your child to sort them: which have four sides, which have square corners, and which have equal sides?
- Use 12 craft sticks to build different rectangles, such as 1 by 5 and 2 by 4, and compare: the perimeter is the same, but is the area?
Where kids can get stuck
- Adding only the two side lengths shown, so a 5 by 3 rectangle gets a perimeter of 8 instead of 16.
- Leaving shapes with four uneven straight sides out of the quadrilateral group, counting only squares and rectangles.
- Assuming rectangles with the same perimeter must have the same area, though a 1 by 5 and a 2 by 4 do not.
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
- attribute
- A feature of a shape, such as its number of sides or square corners.
- polygon
- A flat, closed shape with straight sides.
- quadrilateral
- Any flat, closed shape with 4 straight sides.
- rhombus
- A quadrilateral with 4 equal sides.
- rectangle
- A quadrilateral with 4 square corners.
- square
- A quadrilateral with 4 equal sides and 4 square corners.
- perimeter
- The distance all the way around a shape.
- side length
- How long one side of a shape is.
Ready to build your child’s confidence with shapes and perimeter?
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 Reveal Math Grade 3 Unit 7 cover?
Reveal Math Grade 3 Unit 7 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.