Carlos read 28 books in July and 30 books in August, so in total he read 28 + 30 = 58 books during those two months.
Carlos needed to read 100 books during his summer vacation, so he still needs to read 100 - 58 = 42 books.
Therefore, Carlos must have read 42 books in June to meet his goal.
#### 42
The answer is: 42
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
Carlos read 28 books in July and 30 books in August.  He needed to read 100 books during his summer vacation. If Carlos read some of the books in June, calculate the number of books that Carlos read in June to meet his goal?

### Answer:
