The school bought some chalk, used up 180 boxes and left 40 boxes, how many boxes of chalk did the school buy? (solution by equation)
学校买来一些粉笔，用去180盒还剩40盒，学校买来多少盒粉笔？(用方程解)
<gadget id="calculator">40 + 180</gadget>
<output>220</output>

<result>220</result>