[{"id": 1, "type": "multiple_choice", "skill": "fractions", "options": ["2/4", "1/2", "3/4", "3/8"], "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: 14 × 6", "difficulty": "medium", "explanation": "Multiply: 14×6=84", "needs_review": false, "correct_answer": "84"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 × 17", "difficulty": "medium", "explanation": "Multiply: 19×17=323", "needs_review": false, "correct_answer": "323"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 15 × 3", "difficulty": "medium", "explanation": "Multiply: 15×3=45", "needs_review": false, "correct_answer": "45"}]