The school bought 230 boxes of chalk and used 12 boxes every week for 6 weeks. How many boxes are left?
学校买来230盒粉笔，每星期用12盒，用了6个星期，还剩多少盒？
<gadget id="calculator">12 * 6</gadget>
<output>72</output>

<gadget id="calculator">230 - 72</gadget>
<output>158</output>

<result>158</result>