enVision Mathematics Grade 5, Topic 16: Classify Two-Dimensional Figures
In this unit, your child ends the year with shapes. They classify two-dimensional figures by properties like parallel sides, equal sides, and right angles, and arrange them in a hierarchy: a square is both a rhombus and a rectangle, and every rectangle is a parallelogram. After patterns and graphing, it is a chance to reason with definitions and explain why a shape belongs.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Topic 16?
- Reasoning that any property of a category belongs to every shape inside it, so squares have every property of rhombuses. Learn more: Why a square is also a rectangle
- Classifying triangles and quadrilaterals by sides and angles, and placing them in a hierarchy from quadrilateral down to square. 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
Ines sorts tiles. She knows every rhombus has four sides of the same length. Which tile must also have four sides of the same length?
- A parallelogram tile
- A square tile
- A rectangle tile
How you can help
- Play “I spy a parallelogram” on a walk or ride. Each time someone spots one, ask your child whether it is also a rectangle, a rhombus, or a square, and why.
- Tilt a square card or napkin onto its corner. Ask your child whether it is still a square, and listen for a reason about its sides and angles rather than its position.
- Ask yes-or-no questions at dinner: Is every rectangle a square? Is every square a rhombus? Let your child explain each answer with a quick sketch.
Where kids can get stuck
- Calling a square tipped onto its corner a “diamond,” naming the shape by how it is turned.
- Placing each shape in only one group, so a square goes under squares but not under rectangles.
- Reversing the reasoning, saying all rectangles have four equal sides because squares do.
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
- quadrilateral
- A polygon with four sides and four angles.
- parallelogram
- A quadrilateral whose opposite sides are parallel and the same length.
- rectangle
- A parallelogram with four right angles.
- rhombus
- A parallelogram with four equal sides, which may or may not have right angles.
- trapezoid
- A four-sided shape with at least one pair of parallel sides.
- right angle
- A square corner, like the corner of a sheet of paper.
- parallel
- Lines that always stay the same distance apart and never meet.
- property
- A feature that describes a shape, like having four right angles.
- hierarchy
- A family tree that shows which groups of shapes fit inside others.
Ready to build your child’s confidence with classifying shapes?
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 enVision Mathematics Grade 5 Topic 16 cover?
enVision Mathematics Grade 5 Topic 16 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.