Paper 2 Computational Thinking Thinking Ahead

Determining preconditions

Determining preconditions means identifying the conditions already in place before you plan a solution to a problem.

  • Good problem-solvers do not jump straight to an answer.
  • They pause and look at the conditions already in place.
  • They work out which limits, costs, rules, and user needs will shape the final solution.
Illustration of gears above the word preconditions
Preconditions are the existing conditions that affect your proposed solution.

Dual coding

Think ahead before you build

A problem starts the process, but a strong solution comes from checking the preconditions first. These might be time, money, legal rules, user needs, equipment, or design limits.

1

Problem

What are you trying to solve?

2

Preconditions

What conditions already exist?

3

Solution

What realistic plan can you now make?

Three-course meal presented on a table
A meal sounds simple until you remember the preconditions: cost, cooking time, allergies, ingredients, and equipment.
Map of a theme park used as the lesson scenario
Theme park map for the family planning scenario.

Activity 1

Theme park trip

  • A family of four wants to plan a theme park visit carefully.
  • Read each planning statement in the bank.
  • Drag each one into the correct precondition category.

Time

0

Budget

0

Suitability

0

Interests

0

Statement bank

Drag each statement into the correct category.

Activity 2

Wine merchant event

  • A national wine merchant is planning an event to promote vintage wines.
  • Read each planning statement in the bank.
  • Sort each one into the most relevant precondition category.
Wine glasses at a tasting event
The event plan must consider location, cost, legal issues, and competition.

Location

0

Budget

0

Legal

0

Competition

0

Statement bank

Choose the best category for each one.

Activity 3

Battleships game design

  • Before creating a Battleships game, a programmer must decide some core preconditions.
  • The grid, fleet, ship sizes, and encoding all need deciding before coding starts.
  • Sort the design questions into the best category.
Illustrated submarine

Your board

ABCDE FGHIJ
12345 678910
Illustrated ship
Illustrated ship

Opponent board

ABCDE FGHIJ
12345 678910
Illustrated submarine

Fire at the opponent board to begin the game.

Grid size

0

Number of ships

0

How many vessels each player has.

Ship footprint

0

How ships fit across squares.

Encoding

0

How the program represents data.

Design question bank

Choose the best planning category for each one.

Activity 4

Explain four scenarios

  • Explain at least three preconditions for each scenario.
  • Show how each precondition would affect the final solution.
  • Complete all four scenario boxes.