[{"id": 1, "type": "short_answer", "skill": "area", "question": "Find the area of a rectangle: length=7, width=5", "difficulty": "medium", "explanation": "A=l×w=7×5=35 sq units.", "needs_review": false, "correct_answer": "35"}, {"id": 2, "type": "multiple_choice", "skill": "perimeter", "options": ["12", "35", "24", "28"], "question": "Find the perimeter of a rectangle: length=7, width=5", "difficulty": "medium", "explanation": "P=2(l+w)=2(7+5)=2(12)=24", "needs_review": false, "correct_answer": "24"}, {"id": 3, "type": "short_answer", "skill": "computation", "question": "Calculate: 18 × 4", "difficulty": "medium", "explanation": "Multiply: 18×4=72", "needs_review": false, "correct_answer": "72"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 18 × 19", "difficulty": "medium", "explanation": "Multiply: 18×19=342", "needs_review": false, "correct_answer": "342"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 5 × 14", "difficulty": "medium", "explanation": "Multiply: 5×14=70", "needs_review": false, "correct_answer": "70"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 15 × 5", "difficulty": "medium", "explanation": "Multiply: 15×5=75", "needs_review": false, "correct_answer": "75"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 5 × 11", "difficulty": "medium", "explanation": "Multiply: 5×11=55", "needs_review": false, "correct_answer": "55"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 20 × 12", "difficulty": "medium", "explanation": "Multiply: 20×12=240", "needs_review": false, "correct_answer": "240"}]