[{"title": "Basic Addition", "content": "Add 72 + 64. Start in the ones place: 2 + 4 = 6. Write 6. Continue to the tens place.", "solution": "72 + 64 = 136"}, {"title": "Word Problem", "content": "A library has 221 fiction books and 512 nonfiction books. How many books does the library have in total? Identify the operation: we are combining two quantities, so we add.", "solution": "221 + 512 = 733 books"}]