1. The problem asks to write each number in expanded form and then add: 45 + 54. 2. First, write 45 in expanded form: $45 = 40 + 5$. 3. Write 54 in expanded form: $54 = 50 + 4$. 4. Now add the expanded forms: $(40 + 5) + (50 + 4)$. 5. Combine like terms: $(40 + 50) + (5 + 4) = 90 + 9$. 6. Add the sums: $90 + 9 = 99$. 7. So, the sum of 45 and 54 is 99.