The idea in brief. Compare the opening with a right angle; changing arm lengths or turning the whole figure does not change the angle. Compare the opening, not the lengths of its arms or the way it is turned. In the lesson. In Primary 1, you learned to name shapes like the square. A square has 4 straight sides and 4 corners. Today, we will learn what an angle is, and compare angles with a right angle. Use a square's corner to compare an angle with a right angle. Long arms, short arms or a tilt do not change the angle.
Lesson video, with the working
Angles
3 min 45 s
The film teaches 3 questions in turn. Each question shows first; its working is written as the film explains it.
How do you tell if an angle is greater or smaller than a right angle in P3?
This is where Primary 3 geometry begins.
What your child learns here
This is where Primary 3 geometry begins. It covers the concept of an angle as a turn between two straight arms, and the first way to describe its size: equal to, smaller than or greater than a right angle.
An angle is made by two straight arms meeting at a point.
The size of an angle is the amount of turning from one arm to the other.
A right angle is a quarter turn, the same as the corner of a square.
Any angle can be compared with a right angle: smaller, equal or greater.
Longer arms, or turning the whole figure, do not change the size of the angle.
Does the answer make sense?
Turning the page or drawing longer arms never changes the answer, since an angle's size is only the amount of turn. Your child can lay a book's corner on the meeting point with one edge along one arm: the other arm hidden under the book means smaller, along its edge equal, outside it greater.
How to practise these questions
The Basic questions practise judging whether an angle is smaller than, equal to or greater than a right angle. The Intermediate questions add angles in everyday objects and turned figures, where a set square or a folded paper corner helps. If an angle comparison stalls, watch its solution film and try it again later from Revision. The multiple-choice Intermediate questions ask which of four marked angles is greater than, smaller than or equal to a right angle, or which statement about lettered angles is true, and each one is solved in writing rather than on film.
Questions parents ask
Does my child need a protractor in P3? No. The Primary 3 syllabus covers the concept of an angle and comparing it with a right angle, and the comparison is made with a square corner or a set square. Measuring angles in degrees is in the following year's syllabus.
What is an angle, in words a P3 child understands? An angle is the amount of turn between two straight lines that meet at a point. Opening a book or a pair of scissors wider makes the angle bigger.
Is a right angle always the corner at the bottom of a shape? No. A right angle can face any way and sit anywhere in a figure. Whether it is a right angle depends only on the turn between its two arms.
