There are 2,500 books in the library, 326 books have been borrowed from the fourth grade, and 454 books have been borrowed from the fifth grade. How many books are left in the library?
图书室有2500本书，四年级借走了326本，五年级借走了454本，图书室还剩多少本书？
<gadget id="calculator">326 + 454</gadget>
<output>780</output>

<gadget id="calculator">2_500 - 780</gadget>
<output>1_720</output>

<result>1_720</result>