The school bought 900 new books, 360 of which are placed in the library, and the rest are distributed to six grades. How many books can each grade get on average?
学校新买来900本图书，其中360本放在图书室，其余的分给六个年级，平均每个年级可以分到多少本？
<gadget id="calculator">900 - 360</gadget>
<output>540</output>

<gadget id="calculator">540 / 6</gadget>
<output>90</output>

<result>90</result>