[{"id": 1, "type": "multiple_choice", "skill": "fractions", "options": ["3/4", "3/8", "2/4", "1/2"], "question": "What is 1/4 + 2/4?", "difficulty": "medium", "explanation": "Same denominator: add numerators. (1+2)/4=3/4.", "needs_review": false, "correct_answer": "3/4"}, {"id": 2, "type": "short_answer", "skill": "fractions", "question": "Simplify: 6/8", "difficulty": "medium", "explanation": "Divide numerator and denominator by GCF (2): 6÷2/8÷2=3/4.", "needs_review": false, "correct_answer": "3/4"}, {"id": 3, "type": "short_answer", "skill": "computation", "question": "Calculate: 17 × 9", "difficulty": "medium", "explanation": "Multiply: 17×9=153", "needs_review": false, "correct_answer": "153"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 18 × 16", "difficulty": "medium", "explanation": "Multiply: 18×16=288", "needs_review": false, "correct_answer": "288"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 3 × 4", "difficulty": "medium", "explanation": "Multiply: 3×4=12", "needs_review": false, "correct_answer": "12"}]