[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 70 + 80", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "150"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Identity property", "Distributive property", "Associative property", "Commutative property"], "question": "Which property states a+0=a?", "difficulty": "easy", "explanation": "The identity property of addition states that adding 0 to any number gives that number.", "needs_review": false, "correct_answer": "Identity property"}, {"id": 3, "type": "short_answer", "skill": "computation", "question": "Calculate: 8 × 13", "difficulty": "medium", "explanation": "Multiply: 8×13=104", "needs_review": false, "correct_answer": "104"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 6 × 3", "difficulty": "medium", "explanation": "Multiply: 6×3=18", "needs_review": false, "correct_answer": "18"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 11 × 5", "difficulty": "medium", "explanation": "Multiply: 11×5=55", "needs_review": false, "correct_answer": "55"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 × 11", "difficulty": "medium", "explanation": "Multiply: 19×11=209", "needs_review": false, "correct_answer": "209"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 × 15", "difficulty": "medium", "explanation": "Multiply: 19×15=285", "needs_review": false, "correct_answer": "285"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 20 × 10", "difficulty": "medium", "explanation": "Multiply: 20×10=200", "needs_review": false, "correct_answer": "200"}, {"id": 9, "type": "short_answer", "skill": "computation", "question": "Calculate: 18 × 16", "difficulty": "medium", "explanation": "Multiply: 18×16=288", "needs_review": false, "correct_answer": "288"}, {"id": 10, "type": "short_answer", "skill": "computation", "question": "Calculate: 3 × 14", "difficulty": "medium", "explanation": "Multiply: 3×14=42", "needs_review": false, "correct_answer": "42"}, {"id": 11, "type": "short_answer", "skill": "computation", "question": "Calculate: 11 × 7", "difficulty": "medium", "explanation": "Multiply: 11×7=77", "needs_review": false, "correct_answer": "77"}, {"id": 12, "type": "short_answer", "skill": "computation", "question": "Calculate: 11 × 2", "difficulty": "medium", "explanation": "Multiply: 11×2=22", "needs_review": false, "correct_answer": "22"}]