Year 6 Teaching Sequence Autumn S1 – 2D and 3D shape and angles (five days) Prerequisites: Estimate, draw and measure acute and obtuse angles using a protractor and calculate angles in a straight line (see Year 5 teaching sequence S1) Use knowledge of properties to draw 2-D shapes (see Year 5 teaching sequence S1 and Year 6 oral and mental starter bank S1) Recognise parallel and perpendicular lines in shapes (see Year 5 teaching sequence S2) Recognise reflective symmetry in regular polygons, e.g. know that a square has four axes of symmetry and an equilateral triangle has three (see Year 5 teaching sequence S2) Identify, visualise and describe properties of rectangles, triangles, regular polygons and 3-D solids; use these properties to classify 2-D shapes and 3-D solids (see Year 5 teaching sequence S2 and Year 6 oral and mental starter bank S1) Make 3-D shapes with increasing accuracy (see Year 5 teaching sequence S2) Identify and draw nets of 3-D solids (see Year 5 teaching sequence S2) Use Venn and Carroll diagrams to sort shapes and show information about shapes (see Year 5 teaching sequence S2 and Year 6 oral and mental starter bank S1) Overview of progression: Children identify and draw acute, obtuse and reflex angles. They use the fact that angles in a triangle add up 180° to work out missing angles. Children draw 2D shapes according to given properties. Quadrilaterals including kite, rhombus, trapezium and parallelogram are introduced and children sort them according to their properties including pairs of parallel sides. Children identify nets of closed cubes and make other 3D solids, recording their properties including pairs of parallel faces. Note that using the term vertex rather than corner can, surprisingly, be less confusing when describing 3D shapes. This is because some children can confuse a ‘corner’ with where the sides of two faces meet, rather than a point where the © Original teaching sequence copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users. Y6 Maths TS_S1 – Aut – 5days vertices of at least three faces meet. Likewise it is better to use the term ‘side’ when describing 2D shapes, and the terms ‘faces’ (rather than sides) and ‘edges’, which are where sides of faces meet, when describing 3D shapes. Note that it is more important that children can describe the properties of shapes rather than remember their names. Note that rectangles are four-sided shapes with four right angles and so a square can be thought of as a special kind of rectangle. Rectangles, which are not square, are also called oblongs. Watch out for children who find it difficult to visualise 3D shape from 2D drawings. Watch out for children who only recognise regular pentagons, hexagons, heptagons and octagons. Watch out for children who do not align the protractor properly when measuring angles. © Original teaching sequence copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users. Y6 Maths TS_S1 – Aut – 5days Objectives: Describe, identify and visualise parallel and perpendicular edges or faces Use the properties of 2D and 3D shapes to classify 2D shapes and 3D solids Visualise 3D shapes from 2D drawings and identify different nets for a closed cube Use Venn and Carroll diagrams to show information about shapes Sort and classify quadrilaterals using criteria such as parallel sides, equal sides, equal angles and lines of symmetry Make and draw shapes with increasing accuracy Estimate angles and use a protractor to measure these Draw angles, using a protractor, on their own and in shapes Calculate angles on a straight line, in a triangle or around a point Whole class Group activities Paired/indiv practice Resources How many degrees are in a right angle? What do we call an angle less than 90°? Draw a right angle and an acute angle on your boards. What do we call an angle that is more than 90° but less than 180°? Draw an obtuse angle on your boards. An angle that is more than 180° is called a reflex angle. Sketch one on the board to show this. Also sketch an acute angle and an obtuse angle. Discuss the reflex angle. Do you think that this is more than three right angles? How many degrees would be in three right angles? Ask children to make an estimate of the number of degrees. Use a 360° IWB protractor to show how to measure the angle. Pay particular attention to lining up one of the drawn lines with the diameter of the protractor and the centre cross at the tip of the angle. If your school protractors have numbers in both directions ask them to beware of this! Repeat with the second angle. Draw other reflex angles and ask children up to the board to measure them, pointing out how they are Group of 4-5 children Draw a quadrilateral with two acute angles on your whiteboards. Share children's responses. What are the other two angles? Acute or obtuse? Is it possible to have one of each? Now draw a quadrilateral with one reflex angle. This is called a concave shape, is it ‘caves’ in. What are the other angles? Obtuse or acute? Ask children to work in pairs to find the numbers of acute, obtuse and reflex angles that are possible in quadrilaterals. Easier: Ask children to draw five different looking quadrilaterals and then label each according to the number of obtuse, acute and reflex angles. Discuss what they notice. Harder: Children could also investigate what numbers of acute, obtuse and reflex angles are possible for pentagons, after first making a prediction. Remind them to include irregular pentagons. Ask children to use a protractor to draw the following angles: 49°, 95°, 185° and 265°. They label each acute, obtuse or reflex. They then turn this piece of paper face down. They work in pairs to shuffle a pack of cards (see resources), take one and each try and draw an angle measuring this number of degrees. They use a protractor to measure their angle; the closest person wins a point. Repeat. Ask them to discuss if their estimates are improving with practice. Easier: Children use their original five angles to help, and measure to the nearest five degrees. Cards made from activity sheet (see resources) 360° protractors © Original teaching sequence copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users. Y6 Maths TS_S1 – Aut – 5days aligning the protractor. Ask children to write acute, obtuse or reflex on their whiteboards for each angle. Ask children to use a ruler to draw a triangle on paper. Try and make yours look different from your neighbours. Now measure the size of each angle, and then find the total. What do you notice? Children’s answers might not total 180° exactly, but with enough examples, they may realise that if they could measure the angles very accurately (which is difficult) they should do. Try and draw a triangle that has a different total. Take feedback and agree that the total is always 180°. Ask children to cut their triangles out, and then to tear off each corner. They should then stick the corners together. What happens? So all the triangles that we have drawn have three vertices that can be put together so that the total angle is 180°. This is a useful fact as we can now use this to find one angle in a triangle if we know the other two. Draw a right-angled triangle on the board, marking the right angle with a square. This angle is a right angle, this is the symbol we use, and so it measures 90 °, so what is the total of the other two angles? Draw a regular hexagon on your whiteboards. Now draw an irregular hexagon. Compare it to your Harder: Their measurements of angles should be more accurate. Group of 4-5 children Ask children to draw a horizontal line 5cm long. They then use their protractor to measure 60° from each end, drawing the two lines so that they cross. 60° 60° What type of triangle have you drawn? Measure the third angle to check. Repeat this time asking children to measure 50° from each end, then 40°, 30° and so on. They should work out, then check the third angle each time What happens to the triangle? What word could you use to describe all of these triangles? What will an isosceles triangle look like with two angles each measuring 70°? 80°? Harder: Challenge children to draw an isosceles triangle where only one angle measures 40°. What will the other two angles be? Repeat for triangles with one angle measuring 20°, 80° and 120°. Group of 4-5 children Draw three lines of the same length meeting at © Original teaching sequence copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users. Ask children to work out the missing angles in a triangular jigsaw (see resources), and then use a protractor to check. Easier: Ask children to draw at least six right-angled triangles. Each triangle must be different. They use the protractor to measure one of the acute angles, and then subtract this from 90° to find the other. They use a protractor to check. Activity sheet of a triangular jigsaw (see resources) Children make shapes on geoboards and copy them onto Protractors, rulers Y6 Maths TS_S1 – Aut – 5days partner’s. Is it symmetrical? Does it have any reflex or obtuse angles? Now draw an irregular but symmetrical pentagon. Compare it to your neighbour’s. What’s the same and what’s different? Draw an irregular heptagon that is not symmetrical. Draw an irregular octagon with two lines of symmetry. Draw the following quadrilaterals on the board: square, rectangle, kite and rhombus. Take each in turn and ask children to describe them. Rectangles have four right angles, and so technically a square is a special rectangle, special because all sides are also the same length. We can call a rectangle that is not square an oblong (a shape which is longer than it is wide), but often they are just called rectangles. This is a bit like saying that a circle is a special kind of oval. Point out that the kite has two pair of sides of equal length like a rectangle, but they are adjacent not opposite, and the angles are not 90°. Tell children that this shape is called a kite, easy to remember as it looks kite-shaped! Draw out that the rhombus has four equal sides like a square, but that the angles are not 90°. What do you notice about the angles? Draw out that opposite angles are the same. This shape is called a rhombus, it’s a diamond shape. We could say that a rhombus is a special sort of kite with all sides of the same length, and a square is a special kind of rhombus with all angles of 90°! Draw an inverted kite (delta). a point so that there is 120° between each pair of lines: If I join the ends of the lines, what shape will it make? I’ve drawn a line every 120° round a point. If I draw four lines equally spaced around the point, what shape will I get? What will the central angles be? Why? Try it. Discuss that if every line is the same, then a square is drawn, if the lines are of different lengths, other quadrilaterals can be drawn. How could I use this way to draw a pentagon? How can I find what the central angle needs to be? Divide 360° by 5 to work out what angle you need to measure to draw five equally spaced lines. Repeat with six lines and eight lines, discussing what shapes emerge. Easier: Ask children to draw an equilateral triangle, square, regular pentagon and hexagon and investigate the number of diagonals in each, pointing out that a diagonal is a line joining any two vertices that are not next to one another. (Some children may think that a diagonal is the same as a line of symmetry.) Harder: Point out that each shape is made of © Original teaching sequence copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users. ‘spotty’ paper according to given properties (see resources). They number and name each. Easier: Children take in turns to choose a shape (see resources). They describe it to their partner who has to guess which shape was chosen. Together they copy the shape and record its name and the properties that helped them to identify the shape by the side. They swap roles and repeat. Activity sheet of properties Geoboards, elastic bands and spotty paper Activity sheet of shapes to guess (see resources, easier version only) Y6 Maths TS_S1 – Aut – 5days isosceles triangles, and so the angles at each vertex of each shape can be worked out. Ask children to do this for the pentagon, hexagon and octagon, and use a protractor to check to see if they are correct. What do you think this shape is? Draw out that it is a kite as it has two pairs of sides of the same length, and explain that we call this an inverted kite (or delta) because of the reflex angle. It’s shaped like an arrowhead. Leave the labelled quadrilaterals on the board for reference during the practice activity. Draw a parallelogram and trapezium on the board. Ask children to describe each including what is the same about them and what is different. Discuss how neither is symmetrical (depending on the trapezium you have drawn), and both have a pair of sides that are the same distance away from each other, like a pair of train tracks. Remind children that we call these parallel lines. The first shape has two sets of parallel lines and is called a parallelogram. The second has just one pair of parallel sides and is called a trapezium. Draw a square and a rectangle and draw in the diagonals in the square, rectangle and parallelogram. What do you notice about these diagonals? Draw out that the diagonals in the square cross each other at right angles. Remind children that we call two lines that are at right angles to one another perpendicular. They might also notice that each of the pairs of diagonals cross each other in the middle of the lines – they bisect each other, or cut one Group of 4-5 children Ask children to investigate which quadrilaterals have diagonals that are perpendicular, bisect one another, both and neither. What diagram could we draw to show this? Agree that you could draw either a Venn diagram or a Carroll diagram. Ask children to work in pairs to draw whichever one they prefer. Easier: Ask children to use the pre-drawn shapes in the Activity sheet for the practice activity (see resources). Show them the outline of a Venn or Carroll diagram rather than asking them to come up with their own. © Original teaching sequence copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users. Children use a sorting tree to sort quadrilaterals, and then draw their own Venn diagram to sort them. Easier: Children use an easier sorting tree, and then place shapes on the following Carroll diagram: Has at least one right angle Activity sheet of quadrilateral sorting tree (see resources) Has no right angles Has at least one line of symmetry Has no lines of symmetry Y6 Maths TS_S1 – Aut – 5days another in half. Do the diagonals of a trapezium do this? Draw one on your whiteboard to find out. Draw one each of square, rectangle, parallelogram, trapezium, rhombus and kite. Draw a blank Venn diagram (making you sure you include the outside rectangle as well as two interlocking sets). What criteria could we use to sort these quadrilaterals? Take some suggestions, e.g. at least one pair of parallel sides, at least one line of symmetry, and ask children to help you to sort the shapes accordingly. Show a net of a cube and ask children to sketch it on paper. Point to one of the faces. This face is going to be at the bottom when I make it. Which face do you think will be parallel to this face when I make the shape? Ask children to mark on their copies of the net. Take suggestions, if there is consensus, colour in that face and the base, and make the cube to check. Unfold it again. Point to the base again. Which faces do you think will be perpendicular, at right angles, to this face when I make it up again? Mark them with a cross on your net. Take feedback, mark the four faces with a cross, and make up the cube to check. Show children a collection of 3D shapes and sort them according to a secret criterion, e.g. regular/not regular. Ask them to guess what criterion you have used. Group of 4-5 children Ask each child to choose a 3D shape to make (see resources for nets) and together record the number of faces, vertices and edges for each in a table, e.g. Faces Vertices Edges cube 6 8 12 tetrahedron 4 4 6 triangular 5 6 9 prism Can you spot a relationship between the numbers? If children struggle to see this, suggest they add the number of faces and vertices together; they should then notice that this total is always 2 more than the number of edges. Choose another 3D shape and count the number of faces and vertices. Use the formula to work out the number of edges and then check by counting. A Swiss mathematician called Euler wrote about this in the mid 1700s and showed that this was true for any polyhedron (3D shape © Original teaching sequence copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users. Children identify which nets which will make a cube. They choose one of them and record its properties including how many pairs of parallel faces it has. They work in groups to make a collection of other 3D solids, record their names, and properties including whether they are regular or irregular, the number and shapes of faces, vertices and pairs of parallel faces. They can either use paper nets (see recourses) or a resource such as Polydron or Clixi. Easier: /Harder: Arrange children in mixed ability groups, and encourage those who are most dexterous to make the more difficult shapes, particularly the dodecahedron! Activity sheet of pictures of 3D shapes and nets (see resources) Polydron/Clixi (optional) Scissors Glue sticks Y6 Maths TS_S1 – Aut – 5days with flat surfaces, so not cones, cylinders or spheres) that is not concave (so it doesn’t have any corners that point inwards). It became known as Euler’s formula. Easier: Give the simpler nets to children who find this kind of activity more difficult. © Original teaching sequence copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users. Y6 Maths TS_S1 – Aut – 5days