Master Wang made an average of 156 parts every day, and Master Li made a total of 276 parts in 2 days. On average, how many parts does Master Li make less than Master Wang every day?
王师傅平均每天做156个零件，李师傅2天共做了276个零件．李师傅平均每天比王师傅少做多少个零件？
<gadget id="calculator">276 / 2</gadget>
<output>138</output>

<gadget id="calculator">156 - 138</gadget>
<output>18</output>

<result>18</result>