Directions: This mock exam contains 15 challenging problems in the style of the AMC 8, selected because they involve the reasoning traps and computation types that most frequently cause errors: hidden constraints in number theory, ratio/mass-point geometry, multi-step probability, and system-of-equation edge cases. Work each problem out on paper before selecting an answer. As soon as you choose a choice, the correct answer and a full explanation will appear — use that moment to actively compare your own reasoning to the explanation, not just to check right/wrong. A graphing calculator (Desmos) is available in the bottom-right corner for problems where a quick plot or numeric check helps. When you are done, use the Print/PDF button to generate a blank paper copy with an answer key on the final page for timed practice.