[{"id": 1, "type": "short_answer", "skill": "subtraction", "question": "Calculate: 258 − 50", "difficulty": "medium", "explanation": "Subtract by place value, borrowing as needed.", "needs_review": false, "correct_answer": "208"}, {"id": 2, "type": "multiple_choice", "skill": "subtraction", "options": ["209", "208", "308", "206"], "question": "What is 258 − 50?", "difficulty": "easy", "explanation": "258-50=208", "needs_review": false, "correct_answer": "208"}, {"id": 3, "type": "short_answer", "skill": "computation", "question": "Calculate: 11 × 5", "difficulty": "medium", "explanation": "Multiply: 11×5=55", "needs_review": false, "correct_answer": "55"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 × 8", "difficulty": "medium", "explanation": "Multiply: 19×8=152", "needs_review": false, "correct_answer": "152"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 16 × 16", "difficulty": "medium", "explanation": "Multiply: 16×16=256", "needs_review": false, "correct_answer": "256"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 6 × 11", "difficulty": "medium", "explanation": "Multiply: 6×11=66", "needs_review": false, "correct_answer": "66"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 12 × 12", "difficulty": "medium", "explanation": "Multiply: 12×12=144", "needs_review": false, "correct_answer": "144"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 8 × 14", "difficulty": "medium", "explanation": "Multiply: 8×14=112", "needs_review": false, "correct_answer": "112"}]