[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 54 + 20", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "74"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Commutative property", "Identity property", "Distributive property", "Associative 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: 18 × 19", "difficulty": "medium", "explanation": "Multiply: 18×19=342", "needs_review": false, "correct_answer": "342"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 5 × 13", "difficulty": "medium", "explanation": "Multiply: 5×13=65", "needs_review": false, "correct_answer": "65"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 20 × 6", "difficulty": "medium", "explanation": "Multiply: 20×6=120", "needs_review": false, "correct_answer": "120"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 4 × 4", "difficulty": "medium", "explanation": "Multiply: 4×4=16", "needs_review": false, "correct_answer": "16"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 20 × 11", "difficulty": "medium", "explanation": "Multiply: 20×11=220", "needs_review": false, "correct_answer": "220"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 18 × 5", "difficulty": "medium", "explanation": "Multiply: 18×5=90", "needs_review": false, "correct_answer": "90"}, {"id": 9, "type": "short_answer", "skill": "computation", "question": "Calculate: 11 × 18", "difficulty": "medium", "explanation": "Multiply: 11×18=198", "needs_review": false, "correct_answer": "198"}, {"id": 10, "type": "short_answer", "skill": "computation", "question": "Calculate: 12 × 10", "difficulty": "medium", "explanation": "Multiply: 12×10=120", "needs_review": false, "correct_answer": "120"}, {"id": 11, "type": "short_answer", "skill": "computation", "question": "Calculate: 16 × 20", "difficulty": "medium", "explanation": "Multiply: 16×20=320", "needs_review": false, "correct_answer": "320"}, {"id": 12, "type": "short_answer", "skill": "computation", "question": "Calculate: 14 × 19", "difficulty": "medium", "explanation": "Multiply: 14×19=266", "needs_review": false, "correct_answer": "266"}]