[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 31 + 83", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "114"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Commutative property", "Distributive 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: 11 × 10", "difficulty": "medium", "explanation": "Multiply: 11×10=110", "needs_review": false, "correct_answer": "110"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 4 × 13", "difficulty": "medium", "explanation": "Multiply: 4×13=52", "needs_review": false, "correct_answer": "52"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 10 × 9", "difficulty": "medium", "explanation": "Multiply: 10×9=90", "needs_review": false, "correct_answer": "90"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 10 × 14", "difficulty": "medium", "explanation": "Multiply: 10×14=140", "needs_review": false, "correct_answer": "140"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 8 × 12", "difficulty": "medium", "explanation": "Multiply: 8×12=96", "needs_review": false, "correct_answer": "96"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 11 × 18", "difficulty": "medium", "explanation": "Multiply: 11×18=198", "needs_review": false, "correct_answer": "198"}, {"id": 9, "type": "short_answer", "skill": "computation", "question": "Calculate: 13 × 8", "difficulty": "medium", "explanation": "Multiply: 13×8=104", "needs_review": false, "correct_answer": "104"}, {"id": 10, "type": "short_answer", "skill": "computation", "question": "Calculate: 9 × 15", "difficulty": "medium", "explanation": "Multiply: 9×15=135", "needs_review": false, "correct_answer": "135"}, {"id": 11, "type": "short_answer", "skill": "computation", "question": "Calculate: 20 × 6", "difficulty": "medium", "explanation": "Multiply: 20×6=120", "needs_review": false, "correct_answer": "120"}, {"id": 12, "type": "short_answer", "skill": "computation", "question": "Calculate: 13 × 16", "difficulty": "medium", "explanation": "Multiply: 13×16=208", "needs_review": false, "correct_answer": "208"}]