The bookstore sells 680 story books, which is twice the number of comic books, and sells 70 fewer technology books than the sum of story books and comic books. How many technology books are sold?
书店卖出故事书680本，是卖出连环画的2倍，卖出的科技书比故事书和连环画的总和的3倍少70本，卖出科技书多少本？
<gadget id="calculator">680 / 2</gadget>
<output>340</output>

<gadget id="calculator">340 + 680</gadget>
<output>1_020</output>

<gadget id="calculator">1_020 * 3</gadget>
<output>3_060</output>

<gadget id="calculator">3_060 - 70</gadget>
<output>2_990</output>

<result>2_990</result>