In another charity event, the first grade students donated a total of 350 books, and the second grade students donated 270 more books than the first grade students. How many books did the second grade students donate?
再一次献爱心活动中，一年级同学共捐了350本书，二年级比一年级多捐了270本书，二年级同学捐了多少本书？
<gadget id="calculator">350 + 270</gadget>
<output>620</output>

<result>620</result>