There are 89 boys and 91 girls in the first grade of Hongqi Primary School. Every 45 students are divided into one class. How many classes can be divided into?
红旗小学一年级有男生89人，女生91人，每45人分一个班，可以分多少个班？
<gadget id="calculator">89 + 91</gadget>
<output>180</output>

<gadget id="calculator">180 / 45</gadget>
<output>4</output>

<result>4</result>