There were 235 story books in the school library, and now 280 have been bought and 138 have been lent out. How many story books are there in the library now?
学校图书室原有故事书235本，现在又买来了280本，并借出了138本．现在图书室有故事书多少本？
<gadget id="calculator">280 - 138</gadget>
<output>142</output>

<gadget id="calculator">235 + 142</gadget>
<output>377</output>

<result>377</result>