Shapes and Patterns
Primary 2 · Mathematics
Shapes and Patterns
Lesson 1 of 3
12 min
Let's begin
At break time, Uwase picks up a stick. She draws in the dust of the school yard.
First she pulls the stick along in one long line. Then she swings it round and round.
Her two lines look very different. Today you will learn why, and you will name the shapes those lines can make.
Hold a piece of string. Pull both ends tight.
The string does not bend anywhere. That is a straight line.
A straight line goes the same way from start to finish. It never bends.
The edge of your ruler is straight. The edge of your desk is straight. So is a tight rope.
Now let the string go loose. It sags and bends.
A line that bends is a curved line.
Move your finger round the edge of a 100 Frw coin. Your finger keeps turning. That edge is curved.
The rim of a cooking pot is curved. So is the shell of an egg and the top of a drum.
When two straight lines meet, they make a sharp point. That point is a corner.
Each straight line in a shape is called a side.
To count them, touch each one with your finger and say the number out loud. Touch every side once. Touch every corner once.
Mugisha draws three dots. He joins them with three straight lines.
Count the sides: 1, 2, 3. Count the corners: 1, 2, 3.
A triangle has 3 straight sides and 3 corners.
You see triangles in a warning road sign and in the end of a roof.
Keza cuts a card. She makes every side exactly four fingers long.
Count the sides: 4. Count the corners: 4. And every side is the same length.
That shape is a square. Floor tiles are squares. So is a folded serviette.
Now look at your exercise book. Two of its sides are long. Two are short.
A rectangle has 4 straight sides and 4 corners, but the sides are not all the same. Two are long and two are short.
A door is a rectangle. So is a window, a 2000 Frw note and a football pitch.
A circle is made of one curved line that goes all the way round.
It has no straight sides and no corners. A coin, a plate and a bicycle wheel are circles.
Gatete draws a shape. It has 4 corners. He measures every side and they are all the same length.
4 corners means square or rectangle. All the sides are the same, so it is a square.
Umutoni draws one triangle and one rectangle in her book. How many corners has she drawn altogether?
The triangle has 3 corners. The rectangle has 4 corners.
3 + 4 = 7 corners.
In these shapes, the number of corners is the same as the number of sides.
Triangle: 3 sides, 3 corners. Square: 4 sides, 4 corners. Rectangle: 4 sides, 4 corners.
Tip
Dot the corners as you count!
Put a small dot on each corner with your pencil. Then no corner is counted twice and none is forgotten.
Then ask one more question: are all the sides the same length? Yes, and 4 corners → square. No, and 4 corners → rectangle.
Try each one first, then tap Show answer to check.
Now walk round your home. Find one square, one rectangle, one triangle and one circle. Say each name out loud.
What you learned today
Quick check
How many corners does a triangle have?
