List the conditions, then test the option.
Thinking Skills includes problems that require careful reasoning, rather than a fact recalled from a subject. A useful starting method is to separate every condition, then test an option against all of them in order.
- List: turn each sentence into a short rule.
- Place: draw a tiny line, table or diagram if it makes the rule visible.
- Test: check one option against every rule; stop when a rule fails.
- Explain: say which rule supports or rules out the option.
The NSW Department of Education lists Thinking Skills as one of the current OC sections and links to official practice resources. Use its practice test page for official examples and current information.
Original worked example: rule out an arrangement.
Problem
Three plants — fern, mint and rose — sit in a row of three pots. The fern is not in the middle. The mint is immediately to the left of the rose. Which arrangements can work?
Use the conditions
- Write the rules: F is not middle; M must be immediately left of R.
- The possible adjacent pair is M-R in positions 1–2 or positions 2–3.
- If M-R is 1–2, F is in position 3. This follows both rules: M-R-F works.
- If M-R is 2–3, F is in position 1. That also works: F-M-R.
These are the two arrangements that work. An option such as M-F-R fails because mint is not immediately left of rose. The method identifies the exact failed rule instead of relying on a quick impression.
Common error: reversing a condition.
“Mint is immediately left of rose” does not mean “rose is immediately left of mint”. Keep the direction in the diagram or rewrite the rule as M → R to make the relationship visible.
Self-check: name the rule that decides it.
Before choosing an answer, ask: “Which condition did I use, and have I checked every condition?” If an answer feels right but cannot be tied to a rule, test it again from the beginning.
Build careful reasoning across topics.
The worked problem is original. Official OC format information checked 16 September 2026.