Lesson Plan
Lesson as part of block B2 (new maths framework) taught to top set Y4 class. Observed by
HT and graded ‘outstanding’ due to pace, learning and questioning.
M+O
Practise weekly target- 8x table. Timed questions on worksheet, marked
together.
Lesson:
Draw polygons and classify them by identifying their properties, including
their line symmetry.
Introduction: Put up on IWB a page of regular and irregular polygons (identified with
numbers) and ask children to choose a shape and name one property.
Teacher states a property and asks children to show on their number fan
which shape could fit the criteria e.g. a regular polygon, no lines of
symmetry. Ask children: How do you know it is in this group? What do you
look for?
Show the flash program. Define ‘convex polygon’ as one whose internal
angles are all less than 180˚. Define ‘concave polygon’ as one where one or
more internal angles are more than 180˚. Demonstrate with the flash
program. Use ‘hide details’ button to hide the labels. Can children identify a
variety of concave and convex polygons?
Use ‘regular shape’ button to turn the shape into a regular polygon. Explain
that regular polygons always have equal sides and equal measures. Can we
make this regular shape concave? Explain why you think that?
Describe a range of polygons using given properties
Task:
Above
Complete table to show properties of regular and irregular polygons.
average:
Classify polygons using a Carroll diagram with given criteria
Extension: Create own Carroll or Venn diagram and use to classify polygons.
Average:
Complete table to show properties of regular and irregular polygons.
Find and colour concave polygons, mark lines of symmetry and name a range
of regular and irregular polygons.
Plenary:
Use the properties flashcards.
[Select two cards, such as ‘is a regular polygon’ and ‘has at least one line of
symmetry’.]
Show me a polygon that fits both of these criteria. What do you look for?
Resources:
 IWF
 http://www.mathopenref.com/polygonconvex.html (full screen)
 Properties flashcards
 Worksheets (below)
 Number fans
 Blank Venn and Carroll diagrams
Higher Ability p2
LO: Describe the properties of regular and irregular polygons
1. Complete the table to describe the properties of these shapes.
Number of
Regular or
Number of
Concave or
Shape
lines of
irregular
sides
convex
symmetry
Number of
right angles
Higher Ability p2
2. Classify these polygons using the Carroll Diagram. One has been done for you.
Concave polygon
C
D
F
E
H
G
J
I
K
L
Convex polygon
Has <2 lines of symmetry
B
Has 2 or more lines of
symmetry
A
A
Average Ability p1
LO: Describe the properties of regular and irregular polygons
1. Complete the table to describe the properties of these shapes.
Number of
Regular or
Number of
Concave or
Shape
lines of
irregular
sides
convex
symmetry
Number of
right angles
Average Ability p2
2. Write the name of each polygon. Colour the concave polygons green. Draw any lines of
symmetry in red.
Average Ability p2
Irregular polygon
No lines of symmetry
No right angles
Average Ability p2
One right angle
At least one line of
symmetry
Average Ability p2
Lines of symmetry
Right angles
Number of sides
Average Ability p2
Number of vertices
Concave
Convex
Average Ability p2
Equal sides
More than one right
angle