[{"id": 1, "type": "short_answer", "skill": "multiplication", "question": "Calculate: 4 × 11", "difficulty": "medium", "explanation": "4 groups of 11.", "needs_review": false, "correct_answer": "44"}, {"id": 2, "type": "multiple_choice", "skill": "multiplication", "options": ["15", "33", "44", "48"], "question": "What is the product of 4 and 11?", "difficulty": "easy", "explanation": "4×11=44", "needs_review": false, "correct_answer": "44"}, {"id": 3, "type": "short_answer", "skill": "computation", "question": "Calculate: 16 × 9", "difficulty": "medium", "explanation": "Multiply: 16×9=144", "needs_review": false, "correct_answer": "144"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 13 × 16", "difficulty": "medium", "explanation": "Multiply: 13×16=208", "needs_review": false, "correct_answer": "208"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 16 × 16", "difficulty": "medium", "explanation": "Multiply: 16×16=256", "needs_review": false, "correct_answer": "256"}]