Math · Stage 3

Straight lines, curved lines & the edges of 2D shapes

A line can be straight like a ruler or curved like a smile — and you can describe any flat shape by the kind of lines its edges are made from.

✦ Math📘 Stage 3 · S3⏱ ~10 min🧒 Ages 7–8★ Free to start

I can recognise straight and curved lines and describe a 2D shape by the kind of lines its edges are made from.

Start the free lesson →⬇ Printable PDF

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Kavi's Line Hunt ✏️

Kavi draws two lines. "This one is straight — it never bends, like the edge of a ruler. This one is curved — it bends smoothly, like a smile 🙂!" Then Kavi looks at the edges of a shape. "A triangle's edges are all straight lines. A circle's edge is one curved line!" Kavi hoots: "Let's spot straight and curved lines, then describe shapes by the kind of edges they have!"

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What your child will learn

1Straight line or curved line?A line is a path you can trace with your finger. There are two kinds. Tap each card to meet them!

2What are the edges made from?Every flat (2D) shape is made from edges. Look at each edge: is it a straight line or a curved line? A triangle, square, rectangle and pentagon have edges that are all straight lines. A circle and an oval have one curved line going all the way round. Tap a shape to hear its name.

3Sort by the kind of edges

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A peek inside

Kavi traces the edge of a ruler 📏 and the edge of a smile 🙂. Which edge is a straight line and which is a curved line?

ruler never bends → straight · smile bends smoothly → curved

Try this at home: Is the edge of a ruler a straight line or a curved line?

Ready to play and learn?

Start the free interactive lesson, or print the handout for screen-free play.

Start the free lesson →⬇ Download PDF

Part of Math · Stage 3 · S3 on KAVI Academy — a secular, whole-child learning platform for ages 5–12.