[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 11 + 18", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "29"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Commutative property", "Associative property", "Identity property", "Distributive 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: 9 × 9", "difficulty": "medium", "explanation": "Multiply: 9×9=81", "needs_review": false, "correct_answer": "81"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 16 × 2", "difficulty": "medium", "explanation": "Multiply: 16×2=32", "needs_review": false, "correct_answer": "32"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 10 × 19", "difficulty": "medium", "explanation": "Multiply: 10×19=190", "needs_review": false, "correct_answer": "190"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 4 × 19", "difficulty": "medium", "explanation": "Multiply: 4×19=76", "needs_review": false, "correct_answer": "76"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 20 × 11", "difficulty": "medium", "explanation": "Multiply: 20×11=220", "needs_review": false, "correct_answer": "220"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 12 × 3", "difficulty": "medium", "explanation": "Multiply: 12×3=36", "needs_review": false, "correct_answer": "36"}, {"id": 9, "type": "short_answer", "skill": "computation", "question": "Calculate: 16 × 7", "difficulty": "medium", "explanation": "Multiply: 16×7=112", "needs_review": false, "correct_answer": "112"}, {"id": 10, "type": "short_answer", "skill": "computation", "question": "Calculate: 3 × 16", "difficulty": "medium", "explanation": "Multiply: 3×16=48", "needs_review": false, "correct_answer": "48"}, {"id": 11, "type": "short_answer", "skill": "computation", "question": "Calculate: 12 × 13", "difficulty": "medium", "explanation": "Multiply: 12×13=156", "needs_review": false, "correct_answer": "156"}, {"id": 12, "type": "short_answer", "skill": "computation", "question": "Calculate: 16 × 8", "difficulty": "medium", "explanation": "Multiply: 16×8=128", "needs_review": false, "correct_answer": "128"}]