Finding unknown angles – Grade 4 math lesson

For parents: how to use this lesson

You don't need to know this topic yourself. The lesson explains each step on screen, the way Mr Euclid, our Head of Math, likes it: one tidy step at a time. Every answer is graded straight away with a worked explanation, so you never have to grade anything.

1. Read what your child will learn together.
2. Press Start the lesson below and sit with your child for the teaching and the worked examples (about 19 minutes).
3. Let them do the practice on their own. They choose Getting started, On track or Challenge – start on On track and move up after a few right in a row.
4. Finish with the exit ticket and the talk question: “Why do the angles on a straight line add up to 180°?”
5. Later that day or the next day: the homework (20 minutes), then a practice test.

Watch out for

• Using 360° for a straight line (or 180° for a point). Show it with a paper circle: fold it in half to see 180°.
• Adding the known angle instead of subtracting it. Ask: what is the total, and how much is still missing?

Miss Hypatia's tip for home: Find right angles, straight lines and turns around the house; open a door to different angles.