L.O.1
To be able to recall the 9 times table and
use it to derive associated number facts
9
9
90
Q. Can we use our knowledge of the 9 times
table to say the 90 times table?
9
90 900
.
1
9
2
8
3
7
4
6
5
.
9
81
1
18
9
72
63
8
2
x9 clock
3
7
4
6
54
5
45
27
36
Q. How can we use our x9 clock to work out 40 x 9?
9
81
1
18
9
72
63
8
2
x9 clock
3
7
4
6
54
5
45
27
36
The outer number divided by the inner one is always 9.
9
81
1
18
9
72
63
8
2
x9 clock
3
7
4
6
54
5
45
27
36
Q. How can we use our x9 clock to work out 540 ÷ 9?
9
81
1
18
9
72
63
8
2
x9 clock
3
7
4
6
54
5
45
27
36
L.O.2
To understand and use angle measure in
degrees,
To be able to identify and estimate acute
and obtuse angles
To be able to calculate angles in a straight
line.
REMEMBER…
An ANGLE is an amount of TURN.
Q. What unit do we measure angles in?
degrees are there in
Q. How many
a right angle?
We use the symbol
° to show degrees.
like this 36° or 178° or 317°.
What is the size of this angle?
What is it called?
Q. What is the name of an
angle smaller than 90°?
An angle less than 90° is called an
acute
angle.
Copy into your book:
Angles < 90° are called acute angles
.
START
FINISH
The horizontal line on the right has been
turned through 1 right angle or 90°.
Estimate the size of these angles.
Estimate the size of these angles.
What do we know about A + B?
A
A
B
B
A + B are called COMPLEMENTARY angles.
Q. What size are these angles?
Q. What size is this angle now?
The angle is 180° and is made up of 2 right
angles.
Copy into your books:
Straight line = 2 right angles = 180°
Complementary angles on a straight line are called :
obtuse
acute
Copy into your book:
90° < Angles < 180° are called obtuse angles.
Oral work with 2D shapes.
By the end of the lesson children should be able to:
Know that an angle less than 90° is acute; an angle
between 90° and 180° is obtuse.
Begin to identify and estimate acute, obtuse and
right angles.
Identify acute, obtuse and right angles in 2D shapes.
Calculate angles in a straight line.
L.O.1
To be able to say whether angles are
acute, obtuse or right angles.
To be able to estimate and order angles.
Look at each of these angles.
Decide if each is A acute,
1
3
6
O obtuse or R right-angled.
2
5
4
7
8
Q. What could we use in the classroom to
check that an angle is a right angle?
Q. How many angles has this triangle?
A
Q. What is the name of this angle?
Q. What size is this angle?
We are going to identify each angle and write in its letter.
A
A
B
C
D
E
F
G
H
I
Now we shall estimate to put the letters in order of size.
A
A
B
C
D
E
F
G
H
I
How can we be sure?
L.O.2
To be able to calculate angles in a straight line
To be able to use a protractor to measure and
draw acute and obtuse angles to 5°
We have four strips of card.
They are at right angles.
We are going to move the red one !
.
Q. How many degrees has the red strip turned?
.
Q. How many degrees has the strip turned now ?
.
Q. How many degrees has the strip turned?
.
The strip has moved all the way round to where
it started. How many degrees has it turned?
A whole turn = 4 right angles = 360°
REMEMBER….
It is possible to turn through more than 360°
LOOK…
Q. How many degrees has the red strip turned now ?
The circle has 10
equally spaced points
on its circumference.
Q. If the arrow moves
around all ten points
and ends back where it
started how many
degrees has it turned
through?
Q. If the arrow moves to
the next point on the
circumference how
many degrees has it
turned through?
What is the angle of turn?
The circle has 10
equally spaced points
on its circumference.
Q. If the arrow moves
around all ten points
and ends back where it
started how many
degrees has it turned
through?
360°
Q. If the arrow moves to
the next point on the
circumference how
many degrees has it
turned through?
36°
The angle of turn if the arrow moves to
the next point is
360° ÷ 10 = 36°
The line is a RADIUS.
It connects the
centre of the
circle in a
straight line to a
point on the
circumference.
Where should I draw
another radius to make
an angle of
72° ?
Either of the dotted
lines will give an
angle of 72°.
36° x 2 = 72°
One is clockwise
from our original
radius and the other
is anti-clockwise.
72°
72°
Where should I draw
another radius to make
an angle of
108° ?
Either of the dotted
lines will give an
angle of
108° .
108°
36° x 3 = 108°
One is clockwise
from our original
radius and the other
is anti-clockwise.
108°
Where should I draw
another radius to make
an angle of
144° ?
Either of the dotted
lines will give an
angle of
144° .
36° x 4 = 144°
One is clockwise
from our original
radius and the other
is anti-clockwise.
144°
144°
This circle has 9
equally spaced
points on its
circumference.
Q. If the arrow
the
next point on
moves to
the circumference
how many degrees
has it moved
through?
Q. What is the angle of turn?
This circle has 9
equally spaced
points on its
circumference.
Q. If the arrow
the
next point on
moves to
the circumference
how many degrees
has it moved
through?
40°
Q. The angle of turn if the arrow
moves to the
next point is
360° ÷ 9 = 40 °
Calculate and
write down
the following
angles of turn
moving
clockwise:
A
B
I
C
H
from A to C
from C to F
from B to G
from D to G
from C to I
from A to G
from H to E
D
G
F
E
The points are joined in order. How many sides has the shape?
1
9
2
3
8
7
4
6
5
The shape has 9 sides so is called a NONAGON.
1
9
2
3
8
7
4
6
5
The sides are the same length, the angles are the same so it is REGULAR.
There are 9 internal angles. They are all the same.
1
9
2
3
8
7
4
6
5
Each internal angle is 140°.
The points are joined differently.
What is this shape called?
1
9
2
3
8
7
4
6
5
It has 18 straight edges so it must be a polygon.
1
9
2
3
8
7
4
6
5
Some of the edges turn inwards so it is a CONCAVE POLYGON
There is a regular nonagon inside the shape!
1
9
2
3
8
7
4
6
5
What size are the angles on the circumference of the circle?
Using a corner of paper we see the angles are about 100°.
1
9
2
3
8
7
4
6
5
Estimate then measure the size of some other angles.
The circles are in pairs.
Number the points round
each circle. Start at the
top with 1. Go
clockwise. Be accurate.
Use a sharp pencil.
For column A join each
point to THE NEXT ONE.
For column B join each
point to
THE NEXT BUT ONE
i.e. 1→3, 3→5 and so on.
A
B
You should have
something like this.
What can we say
about the shapes we
have made?
A
B
Copy and complete this table
Number of points and
name of shape
3
4
5
6
7
8
9
10
nonagon
decagon
Angle at centre of circle
360° ÷ 9 = 40°
360° ÷ 10 = 36°
Number of points and
name of shape
3
4
5
6
7
8
9
10
triangle
square
pentagon
hexagon
heptagon
octagon
nonagon
decagon
Angle at centre of circle
360° ÷ 3 = 120°
360° ÷ 4 = 90°
360° ÷ 5 = 72°
360° ÷ 6 = 60°
360° ÷ 7 = 51°
360° ÷ 8 = 45°
360° ÷ 9 = 40°
360° ÷ 10 = 36°
By the end of the lesson children should be
able to:
Begin to identify, estimate and calculate
acute, obtuse and right angles.
Identify acute, obtuse and right angles in
2-D shapes
Estimate the size of angles and begin to use
a protractor to measure angles.
L.O.1
To be able to recall the 7 times table and
use it to derive associated number facts.
7
7
70
.
7
63
1
14
9
56
49
8
2
x7 clock
3
7
4
6
42
5
35
21
28
Answer these in your books:
1.Q. What is 40 x 7?
2.Q. What is 6 x 70?
3.Q. What is 3 x 0.7?
4.Q. What is 90 x 7?
5.Q. What is 5 x 70?
6.Q. What is 8 x 0.7?
7.Q. What is 7 x 0.07?
Q. What is the outer number divided by the
inner number?
1.Q. What is 280 ÷ 7?
2.Q. What is 6.3 ÷ 7?
3.Q. What is 490 ÷ 70?
4.Q. What is 420 ÷ 7?
5.Q. What is 3.5 ÷7?
L.O.2
To be able to calculate angles in a straight
line
To be able to use a protractor to measure
and draw acute and obtuse angles to 5°
The angle for the heptagon is really 51.428571° but we’ll call it 51°!
Number of points and
name of shape
3
4
5
6
7
8
9
10
triangle
square
pentagon
hexagon
heptagon
octagon
nonagon
decagon
Angle at centre of circle
360° ÷ 3 = 120°
360° ÷ 4 = 90°
360° ÷ 5 = 72°
360° ÷ 6 = 60°
360° ÷ 7 = 51°
360° ÷ 8 = 45°
360° ÷ 9 = 40°
360° ÷ 10 = 36°
NOTICE how the angle reduces as the number of points grows
We are going to look
at the pentagon
Draw lines between
two adjacent points on
the circumference to
the centre of the circle
to make an angle.
Q. What did we
calculate this angle to
be?
A
B
You should have something
like this.
Measure the angle to check
it is 72°.
Q. What type of angle is
this?
Now draw in the angle at
the centre for each of the
other shapes in column A.
Measure each of the angles
and compare them with
those in the table.
What do you notice?
72°
There are 5 interior angles
in the regular pentagon.
Q. What type of angles are
these?
X
X
X
Measure and record these
angles.
Q. What size is each angle?
Measure and record the
interior angles of the other
regular polygons.
Q. Are all their interior
angles obtuse?
What do you notice about
them?
X
X
The second shape looks
like a regular pentagon at
the centre with triangles on
the outside.
The outside edge makes a
concave polygon.
Q. How many sides has this
concave polygon?
Measure and record the
angles on the circle.
Do the same for the other
concave polygons in
column B. What do you
notice?
What shapes do you
recognise?
Q. What size do you think these two angles are?
A
B
Q. What must be the sum of the two angles?
In your book draw two diagrams with angles
like the ones on the previous slide.
Measure and record your angles.
Check the angles on your partner’s diagrams.
REMEMBER…
When you are measuring angles with a
protractor it is helpful if you first
ESTIMATE
the size of the angle
then have a way of checking.
By the end of the lesson children should be
able to:
Begin to identify, estimate, order, measure
and calculate acute, obtuse and right
angles;
Calculate angles on a straight line.