1. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
MNU 2-03b
MNU 2-04a
Working with Decimals
Decimal Scales
Rounding to 1 Decimal Place
Addition and Subtraction
Multiplying and Dividing by 10, 100, 1000
Multiplying and Dividing by a single Digit
5-Apr-17
Created by Mr. Lafferty Maths Dept.

2. Created by Mr. Lafferty Maths Dept.
Starter Questions
MNU 2-03b
MNU 2-04a
5-Apr-17
Created by Mr. Lafferty Maths Dept.

3. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
Writing Decimals
MNU 2-03b
MNU 2-04a
Learning Intention
Success Criteria
1. We are learning what a decimal number is. Write down the decimal number represented by a fraction diagram.
Understand what a decimal number is.
2. Write down the decimal number represented by a fraction diagram.
5-Apr-17
Created by Mr. Lafferty Maths Dept.

4. Decimal Numbers www.mathsrevision.com means ten Writing Decimals
MNU 2-03b
MNU 2-04a
When you take a single unit
and divide it into 10 bits,
what we then have are
decimal fractions of a whole number
Imagine, 1 bar of chocolate as our UNIT of measure.
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
or 0.1
5-Apr-17
Created by Mr. Lafferty Maths Dept.

5. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
Writing Decimals
MNU 2-03b
MNU 2-04a
Example : Write down the decimal number
represented by the shaded area.
(a)
(b)
5-Apr-17
Created by Mr. Lafferty Maths Dept.

6. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
Writing Decimals
MNU 2-03b
MNU 2-04a
Example : Write down the decimal number
represented by the diagram.
(a)
(b)
(c)
(d)
5-Apr-17
Created by Mr. Lafferty Maths Dept.

7. Decimal Numbers www.mathsrevision.com Writing Decimals
MNU 2-03b
MNU 2-04a
We can take one bit of the chocolate bar
and split it into 10
1st Decimal place
0.01
0.1
2nd Decimal place
5-Apr-17
Created by Mr. Lafferty Maths Dept.

8. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
Writing Decimals
MNU 2-03b
MNU 2-04a
Example : Write down the decimal number
represented by the diagram.
(a)
(b)
(c)
(d)
5-Apr-17
Created by Mr. Lafferty Maths Dept.

9. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
Writing Decimals
MNU 2-03b
MNU 2-04a
Now try
Exercise 1
Ch2 (page 25)
5-Apr-17
Created by Mr. Lafferty Maths Dept.

10. Created by Mr. Lafferty Maths Dept.
Starter Questions
MNU 2-03b
MNU 2-04a
3cm
5-Apr-17
Created by Mr. Lafferty Maths Dept.

11. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
Reading Scales
MNU 2-03b
MNU 2-04a
Learning Intention
Success Criteria
1 We are learning the steps to read decimal scales.
Understand the steps to work out any decimal scale to 2 decimal places.
2. Solve problems by working out scales.
5-Apr-17
Created by Mr. Lafferty Maths Dept.

12. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
Reading Scales
MNU 2-03b
MNU 2-04a
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
0.1
0.0
1.0cm
2.0cm
You must work out what number goes next to each mark
on the scale.
Step 1: Count the number of steps between numbers.
In this case it takes 10 steps to get from 0.0 to 1.0cm.
Step 2: Do the division
“ the difference between numbers”
by the step number
5-Apr-17
Created by Mr. Lafferty Maths Dept.

13. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
Reading Scales
MNU 2-03b
MNU 2-04a
Find the values of the arrows 8
9cm
10cm
8.3
8.8
9.5
9.8
Step 1: Count the number of steps between numbers.
In this case it takes 10 steps to get from 8 to 9cm. 10
Step 2: Do the division
“ the difference between numbers”
by the step number
9-8=1
5-Apr-17
Created by Mr. Lafferty Maths Dept.

14. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
Reading Harder Scales
MNU 2-03b
MNU 2-04a
3.02
3.04
3.05
3.06
3.07
3.08
3.09
3.11
3.12
3.13
3.14
3.15
3.16
3.17
3.18
3.19
3.01
3.03
3.00cm
3.10cm
3.20cm
You must work out what number goes next to each mark
on the scale.
Step 1: Count the number of steps between numbers.
In this case it takes 10 steps to get from 3.00cm to 3.10cm.
Step 2: Do the division
“ the difference between numbers”
by the step number
5-Apr-17
Created by Mr. Lafferty Maths Dept.

15. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
Reading Harder Scales
MNU 2-03b
MNU 2-04a
12.00cm
12.10cm
12.20cm
12.03
12.08
12.14
12.19
Step 1: Count the number of steps between numbers.
In this case it takes 10 steps to get from 12.00cm to 12.10cm.
Step 2: Do the division
“ the difference between numbers”
by the step number
5-Apr-17
Created by Mr. Lafferty Maths Dept.

16. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
Reading Scales
MNU 2-03b
MNU 2-04a
Now try Exercise 2
Ch12 (page 28)
5-Apr-17
Created by Mr. Lafferty Maths Dept.

17. Created by Mr. Lafferty Maths Dept.
Starter Questions
MNU 2-03b
MNU 2-04a
5-Apr-17
Created by Mr. Lafferty Maths Dept.

18. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
Rounding to 1 decimal place
MNU 2-03b
MNU 2-04a
Learning Intention
Success Criteria
We are learning how to round to 1 decimal place.
1. Remember steps to round to 1 decimal place.
5-Apr-17
Created by Mr. Lafferty Maths Dept.

19. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
Rounding to 1 decimal place
MNU 2-03b
MNU 2-04a
Find the values of the arrows.
8.2cm
8.3cm
8.4cm
8.24
8.28
8.35
Is 8.24 nearer to 8.2 or 8.3 ?
8.2
Is 8.28 nearer to 8.2 or 8.3 ?
8.3
Is 8.35 nearer to 8.2 or 8.3 ?
Neither
5-Apr-17
Created by Mr. Lafferty Maths Dept.

20. Decimal Numbers www.mathsrevision.com Rounding to 1 decimal place
MNU 2-03b
MNU 2-04a
The rules for rounding to 1 decimal place are:
If the 2nd decimal place is 0,1,2,3,4 - leave 1st decimal place as it is
If the 2nd decimal place is 5,6,7,8,9 - add 1 to 1st decimal place
Example : Round the numbers to 1 decimal place
9.04 (b) (c) 24.25
(d) (e) (f)
5-Apr-17
Created by Mr. Lafferty Maths Dept.

21. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
Rounding to 1 decimal place
MNU 2-03b
MNU 2-04a
Now try Exercise 3
Ch2 (page 30)
5-Apr-17
Created by Mr. Lafferty Maths Dept.

22. Created by Mr. Lafferty Maths Dept.
Starter Questions
MNU 2-03b
MNU 2-04a
5-Apr-17
Created by Mr. Lafferty Maths Dept.

23. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
MNU 2-03b
MNU 2-04a
Add and Subtract Decimals
Learning Intention
Success Criteria
1. Understand that you must keep the decimal point lined up when adding and subtracting decimal numbers.
1. We are learning how to add and subtract decimal numbers.
2. Show all working.
5-Apr-17
Created by Mr. Lafferty Maths Dept.

24. Decimal Numbers www.mathsrevision.com Add and Subtract Decimals
MNU 2-03b
MNU 2-04a
Add and Subtract Decimals
When you add or subtract decimal numbers,
it is important to line-up the decimal points.
Example 1 : Calculate
5-Apr-17
Created by Mr. Lafferty Maths Dept.

25. Decimal Numbers www.mathsrevision.com Add and Subtract Decimals
MNU 2-03b
MNU 2-04a
Add and Subtract Decimals
When you add or subtract decimal numbers,
it is important to line-up the decimal points.
Example 1 : Calculate 4 – 0.84
5-Apr-17
Created by Mr. Lafferty Maths Dept.

26. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
MNU 2-03b
MNU 2-04a
Add and Subtract Decimals
Example 1 : Find the value x cm and y cm
x cm
y cm
3.91cm
2.1cm
y cm
3.25cm
2.2cm
x cm
5-Apr-17
Created by Mr. Lafferty Maths Dept.

27. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
MNU 2-03b
MNU 2-04a
Add and Subtract Decimals
Now try Exercise 4
Ch2 (page 32)
5-Apr-17
Created by Mr. Lafferty Maths Dept.

28. Created by Mr. Lafferty Maths Dept.
Starter Questions
MNU 2-03b
MNU 2-04a
40o
5-Apr-17
Created by Mr. Lafferty Maths Dept.

29. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
MNU 2-03b
MNU 2-04a
Multiplying & Dividing by 10, 100, 1000
Learning Intention
Success Criteria
1 We are learning how to multiply and divide decimal numbers by 10, 100, 1000.
Understand the simple rules to multiply and divide decimal numbers.
2. Be able do calculations.
5-Apr-17
Created by Mr. Lafferty Maths Dept.

30. Decimal Numbers www.mathsrevision.com Multiplying by 10, 100, 1000
MNU 2-03b
MNU 2-04a
Multiplying by 10, 100, 1000
To multiply a decimal number by 10,
Simply move point 1 place to the right:
e.g x 10 = point is moved 1 place to right
To multiply a decimal number by 100,
Simply move point 2 places to the right:
e.g x 100 = point is moved 2 places to right
5-Apr-17
Created by Mr. Lafferty Maths Dept.

31. Decimal Numbers www.mathsrevision.com Multiplying by 10, 100, 1000
MNU 2-03b
MNU 2-04a
Multiplying by 10, 100, 1000
To multiply a decimal number by 1000,
Simply move point 3 places to the right:
e.g x 1000 =
point is moved 1 place to right
5-Apr-17
Created by Mr. Lafferty Maths Dept.

32. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
MNU 2-03b
MNU 2-04a
Multiplying by 10, 100, 1000
Example : Multiply by 10, 100, 1000
10 x =
18.574
100 x =
185.74
1000 x =
1857.4
5-Apr-17
Created by Mr. Lafferty Maths Dept.

33. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
MNU 2-03b
MNU 2-04a
Multiplying & Dividing y 10, 100, 1000
Now try Ex 5
First Column in each
Question ONLY
Ch2 (page 35)
5-Apr-17
Created by Mr. Lafferty Maths Dept.

34. Decimal Numbers www.mathsrevision.com Dividing by 10, 100, 1000
MNU 2-03b
MNU 2-04a
Dividing by 10, 100, 1000
To divide a decimal number by 10,
Simply move point 1 place to the left:
e.g. 89 ÷ 10 = 8.9 point is moved 1 place to left
To divide a decimal number by 100,
Simply move point 2 places to the left:
e.g ÷ 100 = point is moved 2 places to left
5-Apr-17
Created by Mr. Lafferty Maths Dept.

35. Decimal Numbers www.mathsrevision.com Dividing by 10, 100, 1000
MNU 2-03b
MNU 2-04a
Dividing by 10, 100, 1000
To divide a decimal number by 1000,
Simply move point 3 places to the left:
e.g ÷ 1000 =
point is moved 3 places to the left
5-Apr-17
Created by Mr. Lafferty Maths Dept.

36. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
MNU 2-03b
MNU 2-04a
Dividing by 10, 100, 1000
Example : Divide by 10, 100, 1000
÷ 10 =
4502.4
÷ 100 =
450.24
÷ 1000 =
45.024
5-Apr-17
Created by Mr. Lafferty Maths Dept.

37. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
MNU 2-03b
MNU 2-04a
Multiplying & Dividing y 10, 100, 1000
Now try Ex 6
First Column in each
Question ONLY
Ch2 (page 35)
5-Apr-17
Created by Mr. Lafferty Maths Dept.

38. Created by Mr. Lafferty Maths Dept.
Starter Questions
MNU 2-03b
MNU 2-04a
57o
5-Apr-17
Created by Mr. Lafferty Maths Dept.

39. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
MNU 2-03b
MNU 2-04a
Multiplication & Division by a Single Digit
Learning Intention
Success Criteria
1. Understand how to multiply and divide a decimal number by a single Digit.
1. We are learning how to multiply and divide a decimal number by a single Digit.
2. Show appropriate working.
5-Apr-17
Created by Mr. Lafferty Maths Dept.

40. Decimal Numbers www.mathsrevision.com
MNU 2-03b
MNU 2-04a
Multiplication & Division by a Single Digit
When multiplying by a single digit
the decimal point always stays in line.
Example : Calculate x 7
5-Apr-17
Created by Mr. Lafferty Maths Dept.

41. Decimal Numbers www.mathsrevision.com
MNU 2-03b
MNU 2-04a
Multiplication & Division by a Single Digit
When dividing by a single digit
the decimal point always stays in line.
Example : Calculate ÷ 6
5-Apr-17
Created by Mr. Lafferty Maths Dept.

42. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
MNU 2-03b
MNU 2-04a
Multiplication & Division by a Single Digit
Example : Copy and complete.
3.5 x 6
18.43 x 4
76.97 x 6
÷ 6
6.52 ÷ 2
95.05 ÷ 5
5-Apr-17
Created by Mr. Lafferty Maths Dept.

43. Created by Mr. Lafferty Maths Dept.
Decimal Numbers
MNU 2-03b
MNU 2-04a
Multiplication & Division by a Single Digit
Now try Ex 7 & 8
Ch2 (page 37)
5-Apr-17
Created by Mr. Lafferty Maths Dept.