[{"id": 1, "type": "short_answer", "skill": "area", "question": "Find the area of a rectangle: length=10, width=4", "difficulty": "medium", "explanation": "A=l×w=10×4=40 sq units.", "needs_review": false, "correct_answer": "40"}, {"id": 2, "type": "multiple_choice", "skill": "perimeter", "options": ["40", "28", "40", "14"], "question": "Find the perimeter of a rectangle: length=10, width=4", "difficulty": "medium", "explanation": "P=2(l+w)=2(10+4)=2(14)=28", "needs_review": false, "correct_answer": "28"}, {"id": 3, "type": "short_answer", "skill": "computation", "question": "Calculate: 17 × 8", "difficulty": "medium", "explanation": "Multiply: 17×8=136", "needs_review": false, "correct_answer": "136"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 7 × 20", "difficulty": "medium", "explanation": "Multiply: 7×20=140", "needs_review": false, "correct_answer": "140"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 20 × 19", "difficulty": "medium", "explanation": "Multiply: 20×19=380", "needs_review": false, "correct_answer": "380"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 11 × 12", "difficulty": "medium", "explanation": "Multiply: 11×12=132", "needs_review": false, "correct_answer": "132"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 18 × 12", "difficulty": "medium", "explanation": "Multiply: 18×12=216", "needs_review": false, "correct_answer": "216"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 5 × 20", "difficulty": "medium", "explanation": "Multiply: 5×20=100", "needs_review": false, "correct_answer": "100"}]