[{"id": 1, "type": "short_answer", "skill": "addition", "question": "Calculate: 87 + 213", "difficulty": "medium", "explanation": "Add by place value, regrouping as needed.", "needs_review": false, "correct_answer": "300"}, {"id": 2, "type": "multiple_choice", "skill": "addition", "options": ["305", "300", "310", "299"], "question": "What is the sum of 87 and 213?", "difficulty": "easy", "explanation": "87+213=300", "needs_review": false, "correct_answer": "300"}, {"id": 3, "type": "true_false", "skill": "properties", "question": "The commutative property means 87+213 = 213+87.", "difficulty": "easy", "explanation": "The commutative property states changing the order of addends does not change the sum.", "needs_review": false, "correct_answer": "True"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 2 × 12", "difficulty": "medium", "explanation": "Multiply: 2×12=24", "needs_review": false, "correct_answer": "24"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 16 × 14", "difficulty": "medium", "explanation": "Multiply: 16×14=224", "needs_review": false, "correct_answer": "224"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 16 × 16", "difficulty": "medium", "explanation": "Multiply: 16×16=256", "needs_review": false, "correct_answer": "256"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 7 × 16", "difficulty": "medium", "explanation": "Multiply: 7×16=112", "needs_review": false, "correct_answer": "112"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 10 × 2", "difficulty": "medium", "explanation": "Multiply: 10×2=20", "needs_review": false, "correct_answer": "20"}]