1. Addition of decimals

2. Appropriate method
 Choosing the correct and easiest way to make the
numbers make sense.
 To calculate a total we would use addition.
 If you have a lot of numbers you can calculate this
in different ways.
 E.g.
 12.1, 23.5, 23.9, 45.8, 67.2, 34.8, 50.7, 45.4 and
24.8

3. 12.1
23.5
23.9
45.8
67.2
34.8
50.7
45.4
24.8
 Traditional Column
method
 Grouping; in small
chunks
 Splitting

4. Adding methods; traditional
column
 the rule is line up the decimal points underneath
one another and put a decimal point in place
ready for the answer. You then start from the
right.
 Example 1 62 + 1.05 + 0.9

5. Work out the answer
93.71
26
4.8
0.95 +

6. Addition methods; splitting
12.1
23.5
23.9
45.8
67.2
34.8
50.7
45.4
24.8
10 + 2 + 0.1
20 + 3 + 0.3
20 + 3 + 0.9
40 + 5 + 0.8
60 + 7 + 0.2
30 + 4 + 0.8
50 + 0 + 0.7
40 + 5 + 0.4
20 + 4 + 0.8

7. Addition methods; grouping
12.1
23.5
23.9
45.8
67.2
34.8
50.7
45.4
24.8
12.1
23.5 59.5
23.9
45.8
67.2 147.8 328.2
34.8
50.7
45.4 120.9
24.8

8. Adding the same thing several times is the same as: Multiplying.
i.e. £40 + £40 + £40 + £40 + £40 + £40 + £40 + £40 + £40 + £40 =
10 × £40
10 × £40 = £400
4 × £60 = £240
2 × £90 = £180
2 × £20 = £40 +
£860

9. Mean
Working out the mean of a set of data
To work out the mean of a set of data, there are two steps:
A) add up all the values (i.e. all the numbers in the list)
B) divide this number by the number of values in the data set.
In this example:
a Adding up all the values will give us:
25 + 37 + 56 + 52 + 43+ 54 + 23 + 40 + 20 + 60 = 410 ÷ 10 =
41

10. Work out the answers
 Work out the mean for each of these sets of
data.
1 The ages of the members of a team are:
35 37 43 24 19 34
What is the mean age of this team?
 2 The distance that staff travel to work is:
12 3 5 23 9 2
What is the mean distance that staff in this team
travel to work?

11. Work out the answers
 In one morning, each member of the team visits
the following numbers of clients:
12 8 6 7 9 6
What is the mean number of clients that the team
visit in this morning?
 4 Over a week, one member of the team visits
the following numbers of clients on
each day:
Monday Tuesday Wednesday Thursday Friday
8 6 7 9 5
What is the mean number of clients she visits per
day in this week?

12. Range
Working out the range of a set of data
The range of a set of data is the difference
between the highest and lowest value
The highest of these values is 60
The lowest of the values is 20
The range for the set of data is: highest value – lowest value.
In this example: 60 – 20 = 40
(i.e. There is 40 years difference between the oldest and youngest
members of the team.)

13. Work out the answers
 The weights of 5 babies born in a maternity unit were:
3.6 kg 3.2 kg 4.0 kg 3.4 kg 3.8 kg
 The heights of children attending a clinic are:
1.25 m 1.15 m 1.19 m 1.21 m 1.17 m 1.23 m
 The time taken by staff to complete a work survey:
32 mins 28 mins 28 mins 30 mins 27 mins 25 mins
36 mins 27 mins 31 mins 33 mins 30 mins 21 mins