[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 79 + 78", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "157"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Identity property", "Distributive property", "Commutative property", "Associative 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: 20 × 6", "difficulty": "medium", "explanation": "Multiply: 20×6=120", "needs_review": false, "correct_answer": "120"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 9 × 20", "difficulty": "medium", "explanation": "Multiply: 9×20=180", "needs_review": false, "correct_answer": "180"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 12 × 19", "difficulty": "medium", "explanation": "Multiply: 12×19=228", "needs_review": false, "correct_answer": "228"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 11 × 5", "difficulty": "medium", "explanation": "Multiply: 11×5=55", "needs_review": false, "correct_answer": "55"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 10 × 20", "difficulty": "medium", "explanation": "Multiply: 10×20=200", "needs_review": false, "correct_answer": "200"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 14 × 6", "difficulty": "medium", "explanation": "Multiply: 14×6=84", "needs_review": false, "correct_answer": "84"}]