[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 99 + 25", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "124"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Commutative property", "Identity property", "Distributive property", "Associative 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: 18 × 5", "difficulty": "medium", "explanation": "Multiply: 18×5=90", "needs_review": false, "correct_answer": "90"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 7 × 15", "difficulty": "medium", "explanation": "Multiply: 7×15=105", "needs_review": false, "correct_answer": "105"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 6 × 20", "difficulty": "medium", "explanation": "Multiply: 6×20=120", "needs_review": false, "correct_answer": "120"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 8 × 12", "difficulty": "medium", "explanation": "Multiply: 8×12=96", "needs_review": false, "correct_answer": "96"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 4 × 2", "difficulty": "medium", "explanation": "Multiply: 4×2=8", "needs_review": false, "correct_answer": "8"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 15 × 17", "difficulty": "medium", "explanation": "Multiply: 15×17=255", "needs_review": false, "correct_answer": "255"}, {"id": 9, "type": "short_answer", "skill": "computation", "question": "Calculate: 20 × 18", "difficulty": "medium", "explanation": "Multiply: 20×18=360", "needs_review": false, "correct_answer": "360"}, {"id": 10, "type": "short_answer", "skill": "computation", "question": "Calculate: 18 × 10", "difficulty": "medium", "explanation": "Multiply: 18×10=180", "needs_review": false, "correct_answer": "180"}, {"id": 11, "type": "short_answer", "skill": "computation", "question": "Calculate: 10 × 14", "difficulty": "medium", "explanation": "Multiply: 10×14=140", "needs_review": false, "correct_answer": "140"}, {"id": 12, "type": "short_answer", "skill": "computation", "question": "Calculate: 7 × 15", "difficulty": "medium", "explanation": "Multiply: 7×15=105", "needs_review": false, "correct_answer": "105"}]