OC thinking skills: true, false or cannot tell?

Quick Answer

A statement is true only if the information given makes it certain. It is false only if the information rules it out. It is "cannot tell" when something needed is missing, even if the statement is probably right in real life.

Who is this practice for?

Children in Years 3 and 4 who are starting to prepare for OC Thinking Skills, and the parent who sits beside them. It needs a pencil and no calculator.

This is a practice format of our own. The real OC test is multiple choice, and this page does not claim that the test asks true, false or cannot-tell questions. The skill it trains is keeping a conclusion inside the evidence, which is part of any reasoning question. For the published format, see the NSW Department of Education page on Opportunity Class practice tests: NSW Department of Education OC practice tests

When is the answer "cannot tell"?

Ask one question: "Do the sentences above make this certain, or rule it out?" If neither, the answer is cannot tell.

Four traps to watch for:

1. Likely, but not stated. Something usually happens, but the sentences do not say it did.
2. "Some" read as "all". "Some of the children" does not tell you about one particular child.
3. A comparison read backwards. Taller than, faster than and older than only work in the direction given.
4. A time or place left out. A fact about a day or a place does not settle a different day or place.

A worked example with all three answers

Information. Dan's team played on Saturday. Dan scored two goals. His team won.

Statement	Answer	Why
Dan's team won on Saturday.	True	The sentences say the team played on Saturday and won.
Dan's team lost on Saturday.	False	The sentences say the team won, so losing is ruled out.
Dan's team scored more than two goals.	Cannot tell	Missing fact: how many goals the other players scored. If none, the team scored exactly two; if any, more.

The twelve information sets

Read the information only. Do not use what you know about the world. For each statement write True, False or Cannot tell. Do the whole set before you look at the answers.

Set 1. Mia, Jack and Priya each have one pet. Mia's pet is a rabbit. Jack's pet is a dog. Priya's pet is not a rabbit and not a dog. Statement: Priya's pet is a different kind of animal from Mia's pet.

Set 2. Every student in Class 3B has a library card. Sam is in Class 3B. Class 3B has twenty-four students. Statement: Sam does not have a library card.

Set 3. Some of the children at the pool wore goggles. Leila was at the pool. Leila swam four lengths. Statement: Leila wore goggles.

Set 4. The red kite is higher than the blue kite. The blue kite is higher than the green kite. The wind was strong. Statement: The green kite is lower than the red kite.

Set 5. Tom is taller than Ben. Ben is taller than Sara. Zoe is shorter than Tom. Statement: Zoe is taller than Sara.

Set 6. The school fete is on Saturday. Stalls open at 9 o'clock and close at 1 o'clock. The cake stall always sells out before 11 o'clock. Statement: The cake stall is open at 2 o'clock.

Set 7. Noah's family drove to the beach on Sunday. They took a picnic and a beach umbrella. They came home at five o'clock. Statement: It was sunny at the beach on Sunday.

Set 8. Ella has 3 more stickers than Omar. Omar has 5 stickers. Ella's stickers are all stars. Statement: Ella has 8 stickers.

Set 9. All of the plants on the windowsill are in blue pots. Some of the plants are ferns. The cactus is on the windowsill. Statement: The cactus is in a green pot.

Set 10. Hana's choir practises every Wednesday. Hana's school has an assembly on the first Monday of each month. Hana's choir has fourteen singers. Statement: Hana's choir practice is after school.

Set 11. There are eight oranges in the bowl. Some of the oranges are sour. The bowl is blue. Statement: Every orange in the bowl is sweet.

Set 12. Every dog at the shelter has a name tag. Biscuit is a dog at the shelter. Some of the dogs at the shelter are brown. Statement: Biscuit has a name tag.

Answers, and what is missing

Set	Answer	Reason, and for cannot tell the missing fact
1	True	Priya's pet is neither a rabbit nor a dog, and Mia's is a rabbit, so they differ.
2	False	Every student in 3B has a card and Sam is in 3B, so "does not have one" is ruled out.
3	Cannot tell	Missing fact: whether Leila is one of the children who wore goggles. "Some" does not say which children.
4	True	Red is higher than blue and blue is higher than green, so red is higher than green.
5	Cannot tell	Missing fact: how Zoe compares with Ben or with Sara. Zoe could be anywhere below Tom.
6	False	Stalls close at 1 o'clock, so the cake stall is not open at 2.
7	Cannot tell	Missing fact: what the weather was on Sunday. A beach umbrella does not say it was sunny.
8	True	Omar has 5 and Ella has 3 more, so Ella has 8.
9	False	All the plants on the windowsill are in blue pots, and the cactus is on the windowsill.
10	Cannot tell	Missing fact: what time of day the Wednesday practice is. Only the day is given.
11	False	Some of the oranges are sour, so it cannot be that every orange is sweet.
12	True	Every dog at the shelter has a tag and Biscuit is a dog there.

Key count: True 4 (sets 1, 4, 8, 12), False 4 (sets 2, 6, 9, 11), Cannot tell 4 (sets 3, 5, 7, 10).

Where a statement was marked cannot tell, ask your child to say the missing fact aloud before you show the answer. If it is the same fact as in the key, they have found the gap. If it is a different fact that would also settle it, that counts too.

Can my child write a cannot-tell statement?

Give your child this set and ask for one true, one false and one cannot-tell statement.

New set. Ruby has a scooter and a bike. The scooter is blue. Ruby rides to school three days a week.

Ask them to name the fact that would settle their cannot-tell statement. Example answers: "Ruby rides the bike on Monday" (cannot tell; missing fact: which days she rides, and on what). Any statement that the three sentences neither prove nor rule out is a fair cannot-tell.

Next steps

• Official format: the NSW Department of Education OC practice tests page.
• OC practice tests and resources
• OC past papers: what exists and what does not
• Free mock test pack
• OC sample questions

Sources and review

Official source (checked 2026-10-15): NSW Department of Education, Opportunity Class practice tests, for the published test format.

Where the questions came from: all twelve information sets and the worked example are original Braintree Coaching Australia material written for this page. None is taken from an official or third-party paper.

Author: James Rush, content writer, Braintree Coaching Australia.

Answer check: every answer was solved a second time before publication, and each missing fact was compared with the author's. A named teacher review has not yet been recorded for this set. If you find an error, please tell us.

Last updated: 2026-10-15.