[{"id": 1, "type": "short_answer", "skill": "area", "question": "Find the area of a rectangle: length=6, width=6", "difficulty": "medium", "explanation": "A=l×w=6×6=36 sq units.", "needs_review": false, "correct_answer": "36"}, {"id": 2, "type": "multiple_choice", "skill": "perimeter", "options": ["12", "36", "24", "24"], "question": "Find the perimeter of a rectangle: length=6, width=6", "difficulty": "medium", "explanation": "P=2(l+w)=2(6+6)=2(12)=24", "needs_review": false, "correct_answer": "24"}, {"id": 3, "type": "short_answer", "skill": "computation", "question": "Calculate: 20 × 11", "difficulty": "medium", "explanation": "Multiply: 20×11=220", "needs_review": false, "correct_answer": "220"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 2 × 7", "difficulty": "medium", "explanation": "Multiply: 2×7=14", "needs_review": false, "correct_answer": "14"}, {"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: 17 × 7", "difficulty": "medium", "explanation": "Multiply: 17×7=119", "needs_review": false, "correct_answer": "119"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 17 × 19", "difficulty": "medium", "explanation": "Multiply: 17×19=323", "needs_review": false, "correct_answer": "323"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 9 × 11", "difficulty": "medium", "explanation": "Multiply: 9×11=99", "needs_review": false, "correct_answer": "99"}]