[{"id": 1, "type": "short_answer", "skill": "area", "question": "Find the area of a rectangle: length=7, width=4", "difficulty": "medium", "explanation": "A=l×w=7×4=28 sq units.", "needs_review": false, "correct_answer": "28"}, {"id": 2, "type": "multiple_choice", "skill": "perimeter", "options": ["28", "22", "28", "11"], "question": "Find the perimeter of a rectangle: length=7, width=4", "difficulty": "medium", "explanation": "P=2(l+w)=2(7+4)=2(11)=22", "needs_review": false, "correct_answer": "22"}, {"id": 3, "type": "short_answer", "skill": "computation", "question": "Calculate: 8 × 15", "difficulty": "medium", "explanation": "Multiply: 8×15=120", "needs_review": false, "correct_answer": "120"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 13 × 4", "difficulty": "medium", "explanation": "Multiply: 13×4=52", "needs_review": false, "correct_answer": "52"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 2 × 15", "difficulty": "medium", "explanation": "Multiply: 2×15=30", "needs_review": false, "correct_answer": "30"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 15 × 12", "difficulty": "medium", "explanation": "Multiply: 15×12=180", "needs_review": false, "correct_answer": "180"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 6 × 5", "difficulty": "medium", "explanation": "Multiply: 6×5=30", "needs_review": false, "correct_answer": "30"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 4 × 18", "difficulty": "medium", "explanation": "Multiply: 4×18=72", "needs_review": false, "correct_answer": "72"}]