There are 180 rhododendrons in the campus, 9 in each row. 4 children go to water the flowers, how many rows do they need to water on average?
校园里在了180棵杜鹃花，每行9棵．4个小朋友去浇花，平均每人要浇多少行？
<gadget id="calculator">180 / 9 / 4</gadget>
<output>5</output>

<result>5</result>