[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 + 52", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "71"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Distributive property", "Associative property", "Commutative 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 × 10", "difficulty": "medium", "explanation": "Multiply: 16×10=160", "needs_review": false, "correct_answer": "160"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 3 × 9", "difficulty": "medium", "explanation": "Multiply: 3×9=27", "needs_review": false, "correct_answer": "27"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 20 × 17", "difficulty": "medium", "explanation": "Multiply: 20×17=340", "needs_review": false, "correct_answer": "340"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 16 × 12", "difficulty": "medium", "explanation": "Multiply: 16×12=192", "needs_review": false, "correct_answer": "192"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 5 × 11", "difficulty": "medium", "explanation": "Multiply: 5×11=55", "needs_review": false, "correct_answer": "55"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 15 × 3", "difficulty": "medium", "explanation": "Multiply: 15×3=45", "needs_review": false, "correct_answer": "45"}, {"id": 9, "type": "short_answer", "skill": "computation", "question": "Calculate: 9 × 20", "difficulty": "medium", "explanation": "Multiply: 9×20=180", "needs_review": false, "correct_answer": "180"}, {"id": 10, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 × 2", "difficulty": "medium", "explanation": "Multiply: 19×2=38", "needs_review": false, "correct_answer": "38"}, {"id": 11, "type": "short_answer", "skill": "computation", "question": "Calculate: 2 × 2", "difficulty": "medium", "explanation": "Multiply: 2×2=4", "needs_review": false, "correct_answer": "4"}, {"id": 12, "type": "short_answer", "skill": "computation", "question": "Calculate: 14 × 15", "difficulty": "medium", "explanation": "Multiply: 14×15=210", "needs_review": false, "correct_answer": "210"}]