4
Two halves make a whole
Learner’s Book 1: Unit 3, pp. 53–55
GoalPut two halves together to make a whole, and colour one half of a shape.
New words
whole · all of a shape, with no parts missinghalf · one of two equal partscolour · fill in with a colour
Explanation
Two halves of the same shape fit together to make the whole shape. Cut a paper square into 2 halves and you can put them back to make the square again. To colour half of a shape, first make sure it has 2 equal parts. Then colour just 1 of them. Be careful! A shape with 3 parts does not show a half. And parts that are not equal are not halves.
Worked examples
Cut a paper square from corner to corner, like the picture. You get 2 triangles that are the same size. Put them together and you have the whole square again.
This circle has 2 equal parts and 1 part is coloured. Half of the circle is coloured.
This bar has 3 equal parts and 1 is coloured. Half is not coloured, because a half needs 2 equal parts.
Class activity
Paper puzzle: cut a paper square into 2 halves along a fold. Colour each half a different colour. Mix them up, then put them back together to make the square. Swap one half with a friend whose square is the same size: can you still make a whole square?
Practice
1
What part of the bar is coloured?
Half.
2
Is half of this bar coloured?
No. The bar has 3 parts, so one part is not a half.
3
Two halves of a cookie are put together. What do you get?
A whole cookie.
4
Colour one half of this bar. How many of the parts do you colour?
1 of the 2 parts.