In the love activity of the Experimental Primary School, the third grade donated 345 yuan, and the fourth grade donated twice that of the third grade. How much did the fourth grade donate?
实验小学献爱心活动中，三年级捐了345元，四年级捐的是三年级的2倍，四年级捐了多少钱？
<gadget id="calculator">345 * 2</gadget>
<output>690</output>

<result>690</result>