Year 2: Naming 2-D shapes and counting sides
Part of the Year 2 2-d and 3-d shapes chapter. Chapter overview · whole chapter on one page
Naming 2-D shapes and counting sides
A 2-D shape is flat. It has length and width, but no depth.
A side is a straight edge. A corner is a sharp point where two sides meet.
A triangle has 3 sides. A square has 4 sides. A pentagon has 5 sides.
A hexagon has 6 sides. A pentagon and a hexagon are shapes with 5 and 6 corners.
A circle and an oval have no straight sides. A semicircle has one straight side and 2 corners.
A square turned on its corner is a diamond. It still has 4 equal sides.
Key ideas
- A triangle has 3 sides.
- A square and a rectangle have 4 sides.
- A pentagon has 5 sides, a hexagon has 6.
- A circle and an oval have no straight sides.
- A semicircle has one straight side and 2 corners.
Method. Trace each straight side with your finger, and count it once.
- Trace the edge with your finger. Go round the outside of the shape once.one trip round the shape
- Count the straight sides. Count each straight side once.3 straight sides
- Write the answer. 3
Check. Count the corners too: there are 3. ✓
Watch out. A curved edge is not a side. Count only the straight parts.
Method. Check the number of straight sides of each shape. Then pick the one that matches.
- Look at each shape. Check the number of straight sides of each one.A: square has 4 sides; B: circle has 0 sides; C: triangle has 3 sides
- Find the one that matches. A circle has no straight sides, so it is the answer.circle matches
- Write the answer. circle
Check. Check each of the other shapes too. Only circle matches. ✓
Watch out. Check every shape, not only the first one you see.
Method. Find every sharp point on the outside of the shape. Count each one once.
- Find each corner. A corner is a sharp point where two sides meet.mark each sharp point
- Count the corners. Each corner is counted once.2 corners
- Write the answer. 2
Check. Count the straight sides as well: there are 1. ✓
Watch out. A corner is sharp. A curved part has no corners.
Watch out
Watch out: a circle has no sides at all. Its edge is one curve, not a straight side. A semicircle has one straight side, not two.
Exam tip
Grown-up tip. Trace each shape with a finger, round the outside. Say the count out loud: “one side, two sides, three sides.” Then count the corners. A curved part has no corners.
Exercise 8A Naming 2-D shapes and sides
Non-calculatorKey words. A flat shape is 2-D. A solid shape is 3-D, so it has depth.
Method. Look at the shape. Think about its sides or faces, then match them to a name.
- Look at the shape. It is a flat (2-D) shape.It is 4 straight sides, all the same length, and 4 corners
- Find the name that matches. Only one shape name has these features.square matches
- Write the name. square
Check. The square has the features we looked for. ✓
Watch out. Look at the whole shape before you name it. Do not guess from one part.
Key words. A flat shape is 2-D. A solid shape is 3-D, so it has depth.
Method. Look at the shape. Think about its sides or faces, then match them to a name.
- Look at the shape. It is a flat (2-D) shape.It is 4 straight sides, two long and two short, and 4 corners
- Find the name that matches. Only one shape name has these features.rectangle matches
- Write the name. rectangle
Check. The rectangle has the features we looked for. ✓
Watch out. Look at the whole shape before you name it. Do not guess from one part.
Method. Trace each straight side with your finger, and count it once.
- Trace the edge with your finger. Go round the outside of the shape once.one trip round the shape
- Count the straight sides. Count each straight side once.3 straight sides
- Write the answer. 3
Check. Count the corners too: there are 3. ✓
Watch out. A curved edge is not a side. Count only the straight parts.
Method. Trace each straight side with your finger, and count it once.
- Trace the edge with your finger. Go round the outside of the shape once.one trip round the shape
- Count the straight sides. Count each straight side once.6 straight sides
- Write the answer. 6
Check. Count the corners too: there are 6. ✓
Watch out. A curved edge is not a side. Count only the straight parts.
Method. Trace each straight side with your finger, and count it once.
- Trace the edge with your finger. Go round the outside of the shape once.one trip round the shape
- Count the straight sides. Count each straight side once.5 straight sides
- Write the answer. 5
Check. Count the corners too: there are 5. ✓
Watch out. A curved edge is not a side. Count only the straight parts.
Method. Trace each straight side with your finger, and count it once.
- Trace the edge with your finger. Go round the outside of the shape once.one trip round the shape
- Count the straight sides. Count each straight side once.4 straight sides
- Write the answer. 4
Check. Count the corners too: there are 4. ✓
Watch out. A curved edge is not a side. Count only the straight parts.
Method. Trace each straight side with your finger, and count it once.
- Trace the edge with your finger. Go round the outside of the shape once.one trip round the shape
- Count the straight sides. Count each straight side once.3 straight sides
- Write the answer. 3
Check. Count the corners too: there are 3. ✓
Watch out. A curved edge is not a side. Count only the straight parts.
Method. Trace each straight side with your finger, and count it once.
- Trace the edge with your finger. Go round the outside of the shape once.one trip round the shape
- Count the straight sides. Count each straight side once.5 straight sides
- Write the answer. 5
Check. Count the corners too: there are 5. ✓
Watch out. A curved edge is not a side. Count only the straight parts.
Method. Check the number of sides of each shape. Then pick the one that matches.
- Look at each shape. Check the number of sides of each one.A: square has 4 sides; B: hexagon has 6 sides; C: triangle has 3 sides
- Find the one that matches. Only the hexagon has 6 sides.hexagon matches
- Write the answer. hexagon
Check. Check each of the other shapes too. Only hexagon matches. ✓
Watch out. Check every shape, not only the first one you see.
Method. Check the sides of each shape. Then pick the one that matches.
- Look at each shape. Check the sides of each one.A: rectangle has two long and two short sides; B: triangle has 3 sides; C: square has 4 equal sides; D: pentagon has 5 sides
- Find the one that matches. Only the square has 4 sides that are all the same length.square matches
- Write the answer. square
Check. Check each of the other shapes too. Only square matches. ✓
Watch out. Check every shape, not only the first one you see.
Method. Look at the edge of the circle.
- Trace the edge. The edge is round all the way round.curved only
- Look for straight sides. A circle has no straight sides.straight sides: 0
- Write the answer. No
Check. A circle has 0 straight sides, so the answer is No. ✓
Watch out. A curved edge is not a straight side.
Method. Trace each straight side with your finger, and count it once.
- Trace the edge with your finger. Every part of the edge is curved.curved all the way round
- Count the straight sides. There are no straight sides to count.0 straight sides
- Write the answer. 0
Check. A shape with no straight sides has no corners either. ✓
Watch out. A curved edge is not a side. Count only the straight parts.
Method. Trace each straight side with your finger, and count it once.
- Trace the edge with your finger. Go round the outside of the shape once.one trip round the shape
- Count the straight sides. Count each straight side once.1 straight sides
- Write the answer. 1
Check. Count the corners too: there are 2. ✓
Watch out. A curved edge is not a side. Count only the straight parts.
Method. Trace each straight side with your finger, and count it once.
- Trace the edge with your finger. Every part of the edge is curved.curved all the way round
- Count the straight sides. There are no straight sides to count.0 straight sides
- Write the answer. 0
Check. A shape with no straight sides has no corners either. ✓
Watch out. A curved edge is not a side. Count only the straight parts.
Method. Trace each straight side with your finger, and count it once.
- Trace the edge with your finger. Go round the outside of the shape once.one trip round the shape
- Count the straight sides. Count each straight side once.4 straight sides
- Write the answer. 4
Check. Count the corners too: there are 4. ✓
Watch out. A curved edge is not a side. Count only the straight parts.
Method. Trace each straight side with your finger, and count it once.
- Trace the edge with your finger. Go round the outside of the shape once.one trip round the shape
- Count the straight sides. Count each straight side once.1 straight sides
- Write the answer. 1
Check. Count the corners too: there are 2. ✓
Watch out. A curved edge is not a side. Count only the straight parts.
Method. A diamond is a square turned on its corner.
- Count the sides. A diamond has 4 straight sides.4 sides
- Check if they are equal. All 4 sides are the same length, the same as a square.4 equal sides
- Decide. So a diamond is a square turned round, and Mia is not right.No
Check. Turn the diamond back and it is a square with 4 equal sides. ✓
Watch out. A shape is still the same shape when it is turned round.
Method. Count all the straight sides of the rectangle.
- Trace the edge with your finger. Go all the way round the rectangle.top, right, bottom, left
- Count the sides. A rectangle has 4 straight sides, not 2.4 sides
- Decide. Ali forgot the two short sides, so he is not right.No
Check. 4 sides is more than 2, so Ali is not right. ✓
Watch out. A rectangle has 4 sides: 2 long and 2 short.