Precedence Tables

1
Precedence Tables
National 5 Lifeskills
Mathematics Geometry
and Measures
2
Getting ready to go for an interview?
National 5 Lifeskills
Mathematics Geometry
and Measures
3
National 5 Lifeskills
Mathematics Geometry
and Measures
It might involve some of these steps
Iron clothes
Get dressed
Shower and wash hair
Dry hair
Travel to interview
Check train/bus timetable
Choose clothes to wear
4

• National 5 Lifeskills
  Mathematics Geometry
  and Measures

But do some steps need to be carried out before
others?
We need to
Shower and wash hair
Before we
Dry hair
5
National 5 Lifeskills
Mathematics Geometry
and Measures
The order of some steps can be changed but there
are some that take precedence over others (i.e.
they must be done before others).
We can show this in a precedence table like this
Dependencies
Task Description Before tasks After tasks Expected time
A
B
C
D
..


6
National 5 Lifeskills
Mathematics Geometry
and Measures
We can put the steps in an order
Choose clothes to wear
Iron clothes
Shower and wash hair
Dry hair
Get dressed
Check train/bus timetable
Travel to interview
7
National 5 Lifeskills
Mathematics Geometry
and Measures
Task Description Before tasks After tasks Expected time (minutes)
A Choose clothes to wear B 5
B Iron clothes A E, G 10
C Shower and wash hair D, E, G 15
D Dry hair C E, G 20
E Get dressed A,B, C F, G 15
F Check train/bus timetable G 5
G Travel to interview A, B, C, D,E, F 30
8
Organising an inter-school badminton competition
National 5 Lifeskills
Mathematics Geometry
and Measures
Order shuttlecocks and trophies
Organise catering arrangements
Compile a list of entrants from replies
Book a sports hall
Plan competition matches
Invite participants and ask for replies
Locate and book officials for matches
9
Put tasks in an order
National 5 Lifeskills
Mathematics Geometry
and Measures
Book a sports hall
Locate and book officials for matches
Invite participants and ask for replies
Compile a list of entrants from replies
Order shuttlecocks and trophies
Organise catering arrangements
Plan competition matches
10
Draw precedence table
National 5 Lifeskills
Mathematics Geometry
and Measures
Task Description Before tasks After tasks Expected time (hours)
A Book a sports hall B, C, D 1
B Locate and book officials for matches F, G 2
C Invite participants and ask for replies A D, G 1
D Compile a list of entrants from replies A, C E, F, G 1
E Order shuttlecocks and trophies A, C, D 2
F Plan competition matches A, B, C, D G 5
G Organise catering arrangements A, B, C, D, 2