Ravi claims that 2n−12^n - 12n−1 is prime for every integer n⩾2n \geqslant 2n⩾2. Disprove Ravi's claim.
Sian claims that if n2 n^2\,n2 is a multiple of 4 then n n\,n must be a multiple of 4. Disprove Sian's claim.
302 exam-style questions on WJEC A Level Maths 1.2 Algebra and Functions, covering 1.2.1 Algebra and Functions, 1.2.2 Algebra and Functions, 1.2.3 Algebra and Functions, 1.2.4 Algebra and Functions, 1.2.5 Algebra and Functions, 1.2.6 Algebra and Functions, 1.2.7 Algebra and Functions, 1.2.8 Algebra and Functions, 1.2.9 Algebra and Functions, 1.2.10 Algebra and Functions, 1.2.11 Algebra and Functions, and 1.2.12 Algebra and Functions. Each one has a worked solution and a mark scheme showing where the marks go.