The library lent out 156 cartoon books, 78 are left, and now 45 are returned. How many cartoon books are there in the library now?
图书室借出156本卡通书，还剩78本，现在又还回45本．现在图书室有多少本卡通书？
<gadget id="calculator">78 + 45</gadget>
<output>123</output>

<result>123</result>