Logic and Proof

Logic and proof questions set the CSSE apart from many other 11+ exams. The CSSE maths paper is designed to test your reasoning ability, not just your calculation skills. This lesson covers the logical thinking skills you need: working systematically, using deduction, spotting patterns, and explaining your reasoning.

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What Is Mathematical Logic?

Mathematical logic means using clear, step-by-step reasoning to solve problems. It involves:

• Deduction: Working out something that must be true based on given information.
• Elimination: Ruling out possibilities until you find the answer.
• Proof: Showing that a statement is always true (or giving a counter-example to show it is false).

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True, False, and Sometimes True

Some statements in maths are always true, some are always false, and some are sometimes true.