Fourth graders explore lines of symmetry — the fold lines that split a shape into two matching halves — discovering that a square has four lines of symmetry while a rectangle has just two.
Students will be able to…
Fold a square in half and the two sides match perfectly. That fold is a line of symmetry! How many ways can you fold different shapes so the halves match?
Project this and pick each shape. See its lines of symmetry — the fold lines where the two halves match perfectly!
Tap any phase to open the teacher moves and student actions.
Fold a square in half — do the sides match?
Teacher models.
Class uses the Symmetry Explorer.
Students find symmetry.
One shape.
Aligned to the Common Core State Standards for Mathematics.
Recognize and draw lines of symmetry for two-dimensional figures.
Classify two-dimensional figures.
Identify lines in two-dimensional figures.
Look for and make use of structure (symmetry).
Preview the three formative checks. Tap “Sample answer” to see what mastery looks like — hide them before you print for students.
Have students find lines of symmetry in capital letters — like A, H, M, and O — and sort letters by how many they have. A printable symmetry sheet is in the Math library.
Tap a card to flip it, then rate whether you knew it. Built from this lesson’s vocabulary.
A quick self-check with instant feedback, drawn from this lesson’s key terms.
A print-and-go review sheet with a built-in answer key. Tap “Show answer key” to reveal answers, or print the clean version for students.