[{"id": 1, "type": "short_answer", "skill": "subtraction", "question": "Calculate: 77 − 43", "difficulty": "medium", "explanation": "Subtract by place value, borrowing as needed.", "needs_review": false, "correct_answer": "34"}, {"id": 2, "type": "multiple_choice", "skill": "subtraction", "options": ["32", "120", "35", "34"], "question": "What is 77 − 43?", "difficulty": "easy", "explanation": "77-43=34", "needs_review": false, "correct_answer": "34"}, {"id": 3, "type": "short_answer", "skill": "computation", "question": "Calculate: 8 × 6", "difficulty": "medium", "explanation": "Multiply: 8×6=48", "needs_review": false, "correct_answer": "48"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 12 × 10", "difficulty": "medium", "explanation": "Multiply: 12×10=120", "needs_review": false, "correct_answer": "120"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 18 × 2", "difficulty": "medium", "explanation": "Multiply: 18×2=36", "needs_review": false, "correct_answer": "36"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 5 × 19", "difficulty": "medium", "explanation": "Multiply: 5×19=95", "needs_review": false, "correct_answer": "95"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 10 × 11", "difficulty": "medium", "explanation": "Multiply: 10×11=110", "needs_review": false, "correct_answer": "110"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 14 × 16", "difficulty": "medium", "explanation": "Multiply: 14×16=224", "needs_review": false, "correct_answer": "224"}, {"id": 9, "type": "short_answer", "skill": "computation", "question": "Calculate: 18 × 8", "difficulty": "medium", "explanation": "Multiply: 18×8=144", "needs_review": false, "correct_answer": "144"}, {"id": 10, "type": "short_answer", "skill": "computation", "question": "Calculate: 17 × 15", "difficulty": "medium", "explanation": "Multiply: 17×15=255", "needs_review": false, "correct_answer": "255"}, {"id": 11, "type": "short_answer", "skill": "computation", "question": "Calculate: 5 × 9", "difficulty": "medium", "explanation": "Multiply: 5×9=45", "needs_review": false, "correct_answer": "45"}, {"id": 12, "type": "short_answer", "skill": "computation", "question": "Calculate: 11 × 18", "difficulty": "medium", "explanation": "Multiply: 11×18=198", "needs_review": false, "correct_answer": "198"}]