Math lesson plan · 3rd grade (Year 4 in England) · 30 minutes
Compare angles with a right angle
Geometry
CCSS 4.G.A.1England: Y3 Geometry
Objective and success criteria
Students will: Compare angles with a right angle.
- I can answer questions on today's skill on my own, without help.
- I can explain each step and say why it works.
- I can check my answer and spot a mistake.
Before and after
Needs first: Polygons: sides and vertices
Leads to: Turns and compass directions
Materials: Rulers and protractors, Squared or dotted paper, Shape cut-outs, Mini whiteboards and pens, Printed student sheet (below).
Warm-up · 4 min
- Quick retrieval from earlier learning (Polygons: sides and vertices). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- How many sides do a triangle and a triangle have altogether? → 6Prompt: How many sides does a triangle have?
- How many sides do a rectangle and a hexagon have altogether? → 10Prompt: How many sides does a rectangle have?
- How many sides do a triangle and a square have altogether? → 7Prompt: How many sides does a triangle have?
Hook · 3 min
- Show a photo of a building, a tile pattern or a road sign and ask what shapes and angles students can spot.
- Share the objective: Compare angles with a right angle. Read the success criteria together.
I do: model it · 7 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: How many right angles does an equilateral triangle have?
- Step 1: 0
- Answer: 0
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 6 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- How many right angles does a regular hexagon have? → 0Prompt: A right angle is a square corner.
- How many right angles make a full turn? → 4Prompt: A quarter turn is one right angle.
You do: independent practice · 7 min
- Students work on the student sheet. Circulate and check the first two answers of every student early.
- Students who finish: write a question of their own for a partner, with the answer.
The 6 questions are on the student sheet below, with answers in the key.
Exit ticket · 3 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- How many right angles does a rectangle have? → 4Prompt: A right angle is a square corner.
- How many right angles make a half turn? → 2Prompt: A quarter turn is one right angle.
Watch out for
- Thinking a square turned on its corner is no longer a square.
- Reading the wrong scale on a protractor.
Support and stretch
Support
- Review first: Polygons: sides and vertices.
- Use concrete materials: rulers and protractors.
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- Move on to: Turns and compass directions.
- Explain a common mistake in writing and how to fix it.
- Write a word problem that uses today's skill, then solve a partner's.
Homework and more practice
Free online practice with hints and printable worksheets for this skill: eurekami.com/math/grade-3.
Free lesson plan from eurekami.com/lesson-plan-builder