[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 + 51", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "70"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Associative property", "Commutative 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: 14 × 11", "difficulty": "medium", "explanation": "Multiply: 14×11=154", "needs_review": false, "correct_answer": "154"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 14 × 8", "difficulty": "medium", "explanation": "Multiply: 14×8=112", "needs_review": false, "correct_answer": "112"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 7 × 19", "difficulty": "medium", "explanation": "Multiply: 7×19=133", "needs_review": false, "correct_answer": "133"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 4 × 20", "difficulty": "medium", "explanation": "Multiply: 4×20=80", "needs_review": false, "correct_answer": "80"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 8 × 9", "difficulty": "medium", "explanation": "Multiply: 8×9=72", "needs_review": false, "correct_answer": "72"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 8 × 4", "difficulty": "medium", "explanation": "Multiply: 8×4=32", "needs_review": false, "correct_answer": "32"}, {"id": 9, "type": "short_answer", "skill": "computation", "question": "Calculate: 7 × 20", "difficulty": "medium", "explanation": "Multiply: 7×20=140", "needs_review": false, "correct_answer": "140"}, {"id": 10, "type": "short_answer", "skill": "computation", "question": "Calculate: 4 × 16", "difficulty": "medium", "explanation": "Multiply: 4×16=64", "needs_review": false, "correct_answer": "64"}, {"id": 11, "type": "short_answer", "skill": "computation", "question": "Calculate: 12 × 4", "difficulty": "medium", "explanation": "Multiply: 12×4=48", "needs_review": false, "correct_answer": "48"}, {"id": 12, "type": "short_answer", "skill": "computation", "question": "Calculate: 14 × 19", "difficulty": "medium", "explanation": "Multiply: 14×19=266", "needs_review": false, "correct_answer": "266"}]