Build an order
- Choose the first item or position to vary.
- List every option for it in a fixed order.
- For each option, list the allowed next choices before moving on.
Worked example
A snack box contains one apple, one banana and one pear. Ava may choose two different fruits. What pairs are possible?
Start with apple: apple–banana, apple–pear. Then start with banana: banana–pear. Starting with pear adds no new pair. There are three pairs, each listed once.
A common error
Listing apple–banana and banana–apple as different choices when order does not matter. Decide first whether the task is about a set, a sequence or a seating position.
Independent self-check
Ask, “What is the next case in my order?” If there is no clear answer, redraw the list as a table. Then check whether any row repeats an earlier result.
Use the method in practice
Ordered search helps with arrangement and possibility problems in NSW Selective and Opportunity Class practice. Use a free test to try original questions, then visit the study overview.