Transcript count on in multiples

Wallands Community Primary School
Mathematical Methods
Information for parents
Reception, Year 1 and Year 2
Mathematical Methods
This booklet is designed to give you
information about the main methods for
calculating in mathematics that your children
are learning in school. The children start with
lots of practical activities and progress to
formal written calculations.
• Addition
+
• Subtraction
• Multiplication
• Division
x
Addition
+
Key Words
add, addition, plus, total, sum
of, more, increase, altogether
First, children should learn to combine
sets of objects by counting.
3 stars
and 4 stars
Altogether make
7 stars
Then children learn the written calculation
3 + 4 =7
Children will learn how to work out what is 1 more
than any number using a number line, or by
counting on in their heads.
5 + 1 =
5 + 1 = 6
+ 1
count on…
Children then learn to add using a count on method.
They may use a number line..
5 + 4 =
count on…
5 + 4 = 9
+ 4
Then children will go on to adding 10 to any number,
using 100 squares.
44 +10 = 54
Later, children will partition into tens and units adding
each separately, e.g.
25 + 13 = 38
20 + 10 = 30
5 + 3 = 8
30 + 8 = 38
Children should learn all the numbers that add
together to make ten off by heart. These are often
known as number bonds.
0 + 10 = 10
1 + 9 = 10
2 + 8 = 10
3 + 7 = 10
4 + 6 = 10
5 + 5 = 10
6 + 4 = 10
7 + 3 = 10
8 + 2 = 10
9 + 1 = 10
10 + 0 = 10
Then they will learn the numbers that add together to
make 20….
Children should learn that
addition can be done in
any order (but it
sometimes helps to put
the larger number first!)
Subtraction
-
Key Words
take away, subtraction,
subtract, minus, decrease,
difference, less than.
First, children should use practical
activities to understand subtraction as a
process of taking away.
5 stars
Take away 3 stars
There are 2 stars left!
Then children learn the written
calculation
5–3=2
Children will learn how to work out what is 1 less
than any number using a number line, or by
counting on in their heads.
5 - 1 =
- 1
5 - 1 = 4
Counting back…
Children then learn to take away using a counting
back method. They may use a number line..
9 - 4 =
-4
count back…
9 – 4 = 5
Then children will go on to take 10 from any number,
using 100 squares.
54 -10 = 44
Knowing that taking away/subtraction is
the inverse or opposite of addition
means that all of those number bonds to
10 come in really handy again.
7 + 3 = 10 so 10 – 7 = 3 and 10 – 3 = 7
And so on……
Some children may use an empty number line method by the end of year 2
35 - 17 =
Here is the answer, 3+10+5 = 18
Remember you can re-order the numbers
in an addition. Put the biggest number first
so 10+5+3 = 18
+10
+3
+5
17 20
30 35
count on…
Most children find it
easier to count on.
When we count on, we are actually finding the difference.
• Place the lowest number on the left of the number line.
• How much do you need to count on to get to the larger number?
Or, you could do it like this…
Here is the answer
-7
18
25
-10
35
…count back
Some children prefer to count back.
• Place the highest number on the right of the number line.
• Count back splitting the number into tens and units.
Multiplication
x
Key Word
multiplication, multiply by,
times, product, multiple, lots
of, groups of, product, array
First children will learn how to count in 1s, 2s,
10s, 5s, 3s and so on…..
1
2
3
4………. (the 1 x table)
2
4
6
8………. (the 2 x table)
10
20
30
40……….(the 10 x table)
5
10
15
20………. (the 5 x table)
3
6
12………. (the 3 x table)
9
Children will begin to group objects, in 2s, 3s etc.
This will help when they progress to formal
multiplication.
2
4
6
Formal multiplication is usually introduced with 3 different
methods:
Children may use repeated addition.
For this a number line or informal jottings can be used, e.g.
…or children may count up in multiples, e.g. 3 x 5
“3… 6… 9… 12… 15!”
…or children may draw an array, e.g. 4 x 2
By year 2, the children will
begin to learn the times tables
facts, beginning with the 2x, 5x
and 10x tables.
1x2=2
2x2=4
3 x 2 = 6 etc etc
When multiplying quick recall of
tables is the most important thing.
Children will start learning these in
Year 2.
Division
÷
Key Words
divide, division, divided by,
divided into, share, group, split
into equal groups, count in
multiples, repeated subtraction
remainder.
Children learn about division through practical activity.
They need lots of practice sharing out to make equal
groups and counting in multiples.
Throughout the foundation stage and Key Stage 1,
children are encouraged to share into equal groups. This
is usually the starting point for learning to divide. At first,
this will be purely practical, but by Year 2, the children
will be introduced to the formal written calculation.
15
3=5
Children are encouraged to ask a division as…
… How many 3’s are there in 15?
Children may also use the repeated subtraction
method.
When using repeated subtraction children use informal
jottings to group, e.g. How many 3’s in 15?
…or children may count on in
multiples like this:
To get really good at
dividing quickly, it really
helps to know those
times tables.