[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 54 + 23", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "77"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Associative property", "Identity property", "Commutative property", "Distributive property"], "question": "Which property states a+0=a?", "difficulty": "easy", "explanation": "The identity property of addition states that adding 0 to any number gives that number.", "needs_review": false, "correct_answer": "Identity property"}, {"id": 3, "type": "short_answer", "skill": "computation", "question": "Calculate: 9 × 7", "difficulty": "medium", "explanation": "Multiply: 9×7=63", "needs_review": false, "correct_answer": "63"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 13 × 8", "difficulty": "medium", "explanation": "Multiply: 13×8=104", "needs_review": false, "correct_answer": "104"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 6 × 16", "difficulty": "medium", "explanation": "Multiply: 6×16=96", "needs_review": false, "correct_answer": "96"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 18 × 18", "difficulty": "medium", "explanation": "Multiply: 18×18=324", "needs_review": false, "correct_answer": "324"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 9 × 17", "difficulty": "medium", "explanation": "Multiply: 9×17=153", "needs_review": false, "correct_answer": "153"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 20 × 9", "difficulty": "medium", "explanation": "Multiply: 20×9=180", "needs_review": false, "correct_answer": "180"}, {"id": 9, "type": "short_answer", "skill": "computation", "question": "Calculate: 7 × 18", "difficulty": "medium", "explanation": "Multiply: 7×18=126", "needs_review": false, "correct_answer": "126"}, {"id": 10, "type": "short_answer", "skill": "computation", "question": "Calculate: 12 × 19", "difficulty": "medium", "explanation": "Multiply: 12×19=228", "needs_review": false, "correct_answer": "228"}, {"id": 11, "type": "short_answer", "skill": "computation", "question": "Calculate: 2 × 15", "difficulty": "medium", "explanation": "Multiply: 2×15=30", "needs_review": false, "correct_answer": "30"}, {"id": 12, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 × 10", "difficulty": "medium", "explanation": "Multiply: 19×10=190", "needs_review": false, "correct_answer": "190"}]