Year 2 Maths Workshop Presentation
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Transcript Year 2 Maths Workshop Presentation
Maths Workshop for Year 2 Parents and
Carers
26 January 2015
Mrs Claire Searle – Maths Leader
What do you understand by:
Multiplication?
Division?
What vocabulary can you think of that applies to
each of them?
What equipment, pictures or images can you
think of that might help children when starting
multiplication and division?
X
repeated addition eg 5 x 3 is the same as
(equals) 3 + 3 + 3 + 3 + 3
times
lots of
groups of
multiplied by
multiply
times tables
double
÷
Repeated subtraction
eg 20 ÷5 = 20 – 5 – 5 – 5 - 5
Divide
Divided by
Share
Share equally
Groups
Lots
Halve
Children need to know:
Each multiplication table from
0 x 2 to 12 x 2
0 x 5 to 12 x 5
0 x 10 to 12 x 10
They need to be able to count in 2s, 5s and 10s, forwards and
backwards – at least to the end of that table, and ideally to 100 for 2
and 5.
They need to know facts such as 2 more than 14, 5 less than 25.
They also need to be able to answer questions quickly such as ‘What
is 10 times 5?’ ‘Twelve lots of 10?’ ‘How many groups of 2 in 22?’
How many fives in 45?
These are multiplication and division facts.
Write the answers:
8 times 10?
How many 2s in 18?
What are nine groups of five?
Sixteen is how many groups of two?
What is 8 multiplied by 5?
Divide 120 by 10.
Seven twos are ... ?
How many 10s in 50?
Children need to know whether a number is
even or odd to know what will happen when it
is multiplied or divided.
They need to know that even numbers will ...
end in 2, 4, 6, 8 or 0.
And odd numbers will ...
end in 1, 3, 5, 7 or 9.
This means multiplication statements for up
to 12 x.
Eg 10 x 5 = 50 5 x 10 = 50
50÷ 10 = 5
50 ÷ 5 = 10
Try this!
Write the multiplication and corresponding division statements for:
8 and 5
6 and 10
8 x 5 = 40
5 x 8 = 40
6 x 10 = 60 10 x 6 = 60
40 ÷ 5 = 8 40 ÷ 8 = 5
60 ÷ 6 = 10 60 ÷ 10 = 6
Use x ÷ = to make these correct
6 x 5 = 30
6 5 30
8÷2=4
824
100 10 10 100 = 10 x 10 or 100
÷ 10 = 10
Use 5 8 and 40 to make these correct
8 x 5 = 40 or 5 x 8 = 40
x =
40 ÷ 8 = 5 or 40 ÷ 5 = 8
÷ =
Commutative – a tricky word that children in Year 2
are not expected to know – but they do need to
understand the idea behind it.
Any ideas?
Addition and multiplication are commutative operations. This
means that for these operations the numbers can be added or
multiplied in any order and the answer will still be the same.
(You can think of it like the word ‘commuter’ – like people the
numbers can go back and forth or change place and still be the
same!)
So 8 + 4 = 12 is the same as 4 + 8 = 12
And 8 x 5 gives the same answer as 5 x 8.
But subtraction and division are not commutative.
8 – 4 (= 4) is not the same as 4 – 8. (-4)
And 40 ÷ 5 (= 8) is not the same as 5 ÷ 40 (= 0.125)
Children need to be taught this – they don’t automatically know
or recognise it, and often won’t notice or realise that they have
written the calculation the wrong way round.
Try these calculations for yourself just to
check what happens...
8 x 10 =
10 x 8 =
50 ÷10 =
10 ÷ 50 =
80
80
5
0.2
Problems – word problems or problems
involving reasoning or working things out
from known facts.
Contexts might mean using multiplication
and division in other subjects, such as
science, PE or history.
Could be problems involving measures,
mass/weight, height/length, data.
These are examples of arrays found in the
environment.
What multiplications do
they show?
The
multiplications for
this array would
be 2 x 4 = 8
or 4 x 2 = 8
Oh dear! The naughty
pup has chewed some
of Sam’s stamps. How
many stamps did Sam
have to start with?
What are the 2 possible multiplications for this array?
What multiplication tables will help children with these
questions?
Draw arrays to show these multiplications:
2x6
6x5
3 x 10
Pupils use a variety of language to describe multiplication and
division.
Pupils are introduced to the multiplication tables. They practise to
become fluent in the 2, 5 and 10 multiplication tables and connect
them to each other. They connect the 10 multiplication table to place
value, and the 5 multiplication table to the divisions on the clock face.
They begin to use other multiplication tables and recall multiplication
facts, including using related division facts to perform written and
mental calculations.
Pupils work with a range of materials and contexts in which
multiplication and division relate to grouping and sharing discrete
and continuous quantities, and relating these to fractions and
measures (e.g. 40 ÷ 2 = 20, 20 is a half of 40). They use commutativity
and inverse relations to develop multiplicative reasoning (e.g. 4 × 5 =
20 and 20 ÷ 5 = 4).
2
5
2
5
5
5
6
5
6
6
+ 2 + 2 + 2 + 2 = 10
groups of 2 or 5 x 2 = 10
multiplied by 5 or 5 multiplied by 2
pairs
hops of 2
+ 5 + 5 + 5 + 5 + 5 = 30
groups of 5 or 6 x 5 = 30
multiplied by 6 or 6 multiplied by 5
groups of 5
hops of 5
10p + 10p + 10p +10p + 10p = 50p
5 times 10p = 50p
5 hops of 10p
5 x 10p = 50p
On an empty numberline, draw the hops for this calculation and
write the different ways you could work this out:
5p + 5p + 5p + 5p + 5p +
5p + 5p = 35p
7 times 5p = 35p
7 hops of 5p
7 x 5p = 35p
Multiplication and division are inverse
operations. This means they are the reverse
of each other.
Addition and subtraction are also inverse
operations.
So an answer can always be checked by
carrying out the calculation the other way
round. 8 x 10 = 80
80 ÷ 10 = 8 or 80 ÷ 8 = 10
One for you, and you and you and you and me.
Keep going until they have all been used up. If there are any
objects left over they are called the ‘remainder’.
You can use any objects to
represent the cakes, but ask a
child to do this practically first –
using concrete objects helps
make the connection between
real objects and the symbols we
use in maths.
Keep taking out groups
of the same number.
How many groups are
there? Any left over
that won’t make
another group of the
same number are the
remainder.
There are 4 apples in each pack. Mrs Pullen buys 3
packs of apples. How many apples does she buy?
KS1 2001 level 2b
Encourage your child to draw their
answer. Have a go at drawing an
answer to one of these questions
now.
There are 35 children. They get into teams of 5. How many
teams are there altogether?
KS1 2003 level 3
Talk to someone else – what do you think?
Which
thought
bubble
shows the
cake
being
shared
equally?
What are
two parts
that are
equal
called?
What
about the
parts of
the cake
cut in 4?
What are
they
called?
What do you think?
Exploring equivalence using a tangram
What fraction is each
part of the whole?
What other fractions
can you make?
What equivalences
can you find?
•
A fraction is made up of 2 numbers. The top number is
called the NUMERATOR and the bottom number is called
the DENOMINATOR. In the fraction ¾, 3 is the numerator
and 4 is the denominator.
•
DENOMINATOR
This number shows how many equal ‘pieces’ something has
been divided into. In the fraction ¾, 4 is the denominator
showing that there are 4 equal pieces making up the whole.
•
NUMERATOR
This number shows how many of those pieces there are. In
the fraction ¾ there are 3 pieces out of the total of 4.
How many
stars make up
1/3 of the
group?
What is half of 12?
Write simple fractions eg 1/2 of 6 = 3 and
recognise the equivalence of 2/4 = 1/2
Equivalent fractions
½ = 2/4 = 3/6 = 4/8 = 5/10 = 6/12 = ...
¼ = 2/8 = 3/12 = 4/16 = 5/20 = ...
1/3
= 2/6 = 3/9 = 4/12 = 5/15 = ...
¾ = 6/8 = 9/12 = 12/16 ...
Make fraction strips showing quarters, thirds, sixths,
Questions for end of KS1
http://www.bbc.co.uk/bitesize/ks1/maths/
http://www.topmarks.co.uk/mathsgames/5-7-years/multiplication-anddivision
http://www.maths-games.org/times-tablesgames.html
http://www.maths-games.org/fractiongames.html
http://primarygamesarena.com/Key-Stage-1