PRESENTATION FROM

PARENT INFORMATION SESSION

Multiplication

Held in the Staff Room at Mt Pleasant Primary School

Wednesday 2 April 2014

Presented by Steve Clee

Teacher: Year 5/6 Room 1

This document relates to the presentation given at the information session. If you have

any questions, please see the presenter listed above.

Basic Facts

• What are they?

• Addition and subtraction facts

• Up to 20

• E.g 10 + 10 and 20 – 10

• Multiplication and division facts

Multiplication Facts

• 0 x 0 to 9 x 9

• 10 x can be included

• 11 x – interesting pattern but not essential

• 12 x - was essential for Imperial

Measurement System – no longer required

Reasons for Grid Format

• It better shows

Commutative Property Of Multiplication

(Reason 1)

• The order in which multiplication is

performed does not effect the result.

• Many students who learn the 3 x tables do

not realise that 8 x 3 is the same as 3 x 8.

• You only have to learn one fact not two.

Commutative Property Of Multiplication

(Reason 2)

• Traditional tables format leads to chanting

through a list of facts to arrive at the

appropriate fact

• To find 6 x 8, they start at 1 x 8 = 8,

• 2 x 8 = 16, 3 x 8 = 24….

Commutative Property Of Multiplication

(Reason 3)

• The patterns and relationship between

basic multiplication facts such as 2 x, 4 x,

8 x and 3 x, 6 x, 9 x is less obvious in table

format

Commutative Property Of Multiplication

(Reason 4)

• The grid format also helps link

multiplication and division

Reducing the Memory Load

• At first glance there is 100 basic

multiplication facts to learn

• Multiplication property of zero reduces by

19

• 81 left to learn

• Multiplication property of one reduces by

17

• Only 64 left to learn

• Commutative property of multiplication

reduces it by almost ½

• Only 36 left to learn

What is left to be learned

• Square numbers

• Multiples of two

• Multiples of five

• Multiples of three

Strategies that assist with the learning of

Basic Multiplication Facts

• Doubling and Halving

• Use of Patterns

• Relate to Known Facts

Doubling And Halving

• Double 2 X 6 = 6 X 2

• Double and Double Again

• 4 x 7 = 2 x (2 x 7)

• Double, Double and Double Again

• 8 x 7 = 2 x {2 x (2 x 7)}

Use Of Patterns

• Useful for 10 x tables

• A calculator is an ideal tool

• It shows patterns

• 3 x 10 = 30

• 3 x 10 = = 300

Word of Caution

• Students will tell you this pattern is ‘adding

a zero’

• Discourage this thinking

• Encourage them to think that when

multiplying by 10 all digits move one place

to left.

Useful for Other Facts

• 5x – halving and the 5,0,5,0 …pattern

• 9x – link to 10x

• 6 x 9 = 6 x 10 – 6

• This leads to the next strategy

Relate To Known Facts

• This is a powerful strategy

• However a student must know some

basic multiplication facts

• 6 x 8 = 5 x 8 + 8

• The more facts a student knows the larger

the base for deriving new facts

Square Numbers

• A good starting point

• If they know 6 x 6. It is easier to work out

• 6 x 7

• Drawing square numbers in an array is a

good way to show why they are called

square.

What to Learn and When?

• Multiplication property of 1

• Multiplication property of 0

• 10 x tables, 5 x tables

• Cluster 2, 4 and 8

• Square numbers

• Cluster 3, 6 and 9

They Must Learn!

• How to double

• The commutative property of multiplication