[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 59 + 26", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "85"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Distributive property", "Commutative property", "Associative property", "Identity 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: 16 × 4", "difficulty": "medium", "explanation": "Multiply: 16×4=64", "needs_review": false, "correct_answer": "64"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 4 × 18", "difficulty": "medium", "explanation": "Multiply: 4×18=72", "needs_review": false, "correct_answer": "72"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 18 × 15", "difficulty": "medium", "explanation": "Multiply: 18×15=270", "needs_review": false, "correct_answer": "270"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 5 × 10", "difficulty": "medium", "explanation": "Multiply: 5×10=50", "needs_review": false, "correct_answer": "50"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 12 × 19", "difficulty": "medium", "explanation": "Multiply: 12×19=228", "needs_review": false, "correct_answer": "228"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 × 15", "difficulty": "medium", "explanation": "Multiply: 19×15=285", "needs_review": false, "correct_answer": "285"}]