TMUA-P2-PRF4-001 — Paper P2 · Disproof by counterexample · Level 1

Options

1. A
   $9$ is odd but not prime.
2. B
   $2$ is prime and even.
3. C
   There are infinitely many odd primes.
4. D
   $1$ is neither prime nor composite.
5. E
   $4$ is even and composite.

Letters only — the answer key is hidden. Work it out, then check the solution below.

Keep practising

• Same topic · same level

  P2PRF4Level 1

  TMUA-P2-PRF4-002

  Disprove the claim: “For all positive integers a, b, c, if a | bc then a | b or a | c.”

  Disproof by counterexample

  Open TMUA-P2-PRF4-002 →

• Same trap: single-counterexample

  P2ARG1Level 3

  TMUA-P2-ARG1-009

  A textbook exercise states the following facts about positive integers, where P is “ n is divisible by 6 ” and Q is “ n…

  Statements and connectives

  Open TMUA-P2-ARG1-009 →

• Step up a level

  P2PRF4Level 2

  TMUA-P2-PRF4-003

  Disprove the claim: “For every real number x, |x| > x.”

  Disproof by counterexample

  Open TMUA-P2-PRF4-003 →