Download teaching written calculations - St. Augustine`s Catholic Primary School

TEACHING WRITTEN
CALCULATIONS
St. Augustine’s Catholic
Primary
Introduction
• Common approach – so the children don’t get
confused
• Mainly start recording fromY1 onwards
• Stages relate to year groups but not all
children at year group level
• Cover all calculations today – am available
afterwards, or speak to class teacher
• Presentation on school website
ADDITION
Stage 1 –Teachers demonstrate
number lines
8 + 5 = 13
0 1 2 3 4 5 6 7 8 9 10 11 12 13
Stage 2 – Children use empty
number lines starting with the
largest number and counting on
34+23 = 57
34
44
54 55 56 57
34
44
54
57
54
57
34
Stage 3
Make sure children count from largest number
first.
Example
38 + 86 = swap to
86 + 38 =
Children begin to work in columns
+
6
7
2
4
1
1
(7+4)
8
0
(60 +
9
1
20)
Stage 4 – Children begin to carry below
the line
7
+
8
1
8
3
4
2
2
5
Stages 5 and 6
Children use larger numbers
Children use decimal numbers
Have a go!!
How would you use a number line to
demonstrate 28 + 54 =
Use the column method to calculate
345 + 67 =
SUBTRACTION
Stage 1 – Teachers demonstrate
number lines
13 – 5 = 8
0 1 2 3 4 5 6 7 8 9 1011 12 131415
Stage 2 – Children use empty number
lines
47-23 =
24 25 26 27
37
47
24
27
37
47
24
27
47
Counting on
82-47 =
47 48 49 50
60
70
80 81 82
Stage 3 – Children use column method
71 – 46 =
-
7
0
1
4
0
6
Stages 4,5 and 6 – Larger numbers,
leading to short method
-
7
5
4
2
8
6
Have a go!!
How would you use a number line to
demonstrate 58 – 24 =
Use the short column method to calculate
654 – 482 =
MULTIPLICATION – Stage 1 and 2
Children must understand that
multiplication is repeated addition
5x3 =5+5+5
0
5
10
15
Need to understand that:
3x5 is the same as 5x3
0
3
6
9
12
15
Stages 3 and 4 – Children continue
to use number lines and arrays
X
6
1
0
4
Grid method
23 x 8 =
x
8
1
1
+
1
2
0
6
0
3
2
6
0
2
4
8
4
4
Short method
38 x 7 =
3
x
2
8
7
6
5
6
Grid method for TU X TU
X
2
0
5
0
1
0
0
0
3
5
0
3
5
0
7
1
1
+
1
6
1
1
3
5
0
1
6
2
5
1
2
1
2
0
4
2
6
2
Stages 5 and 6 – Short method
56 x 27 =
Children approximate first:
60 x 30 = 1800
5
6
X
2
7
3
9
2
56x7
1
1
2
0
56x20
1
5
1
2
1
Have a go!!!
Use the grid method to calculate
43 x 6
Try the short method
Calculate 56 x 43 using the grid method and
short method
DIVISION – Stage 1 and 2 –
Children understand that division is
repeated subtraction 4 groups of 3 in 12
12
3=4
0 1 2 3 4 5 6 7 8 9 10 11 12 13
Stage 3 – Children continue to use
repeated addition on number lines
including remainders
13
0 1
4=3r1
5
9
13
Stage 4 – Short division using
chunking
method
3 = 24
72
3) 72
- 30
42
- 30
12
- 6
6
6
0
10 x
10 x
2x
2x
Answer = 24
Stages 5 and 6 – Children use
larger multiples and numbers
864
24)864
- 720
144
- 72
72
- 72
0
24 = 36
30 x
3x
3x
Answer = 36
Other Year 6 methods
Please look at the leaflets/website. These are
used if children are having difficulties with the
chunking method
Have a go!!
Use a number line to demonstrate
14 7 = 2
Use the chunking method to work out
65 5 =
210 15 =