There are 1,820 story books in the school library, twice as many as science books. After lending some technical books, there are 900 technical books left. How many technical books are lent out?
学校图书馆有故事书1820本，是科技书的2倍．借出一部分科技书后，剩下科技书900本．借出科技书多少本？
<gadget id="calculator">1_820 / 2</gadget>
<output>910</output>

<gadget id="calculator">910 - 900</gadget>
<output>10</output>

<result>10</result>