To determine how many boxes she will need, first step is to calculate how many books Miss Dennison has in total, that is the math books + the science books:
![24+27=51](https://img.qammunity.org/2023/formulas/mathematics/college/95nlevz0dfdel44x7aetdhc6ci3ehqdiag.png)
She can only pack 9 books per box, to determine how many boxes she needs you have to divide the number of books by the number of books that fit each box:
![(51)/(9)=5.67](https://img.qammunity.org/2023/formulas/mathematics/college/oyrfzb0d5jhlthfmznytkcc7kahsapystc.png)
This means that she will fill 5 boxes with 9 books and a sixth one will have only 6 books.
She will use a total of 6 boxes.