Master Wang moved 40 pieces of glass, and he was charged 4 yuan for moving one piece. If he broke one piece without the handling fee, he would have to pay 6 yuan. In the end, Master Wang got 140 yuan. He asked how many pieces he broke?
王师傅搬40块玻璃，搬一块得4元，如果打碎一块没有搬运费，还要赔6元，最后王师傅拿到了140元，问王师傅打碎了几块？
<gadget id="calculator">40 * 4</gadget>
<output>160</output>

<gadget id="calculator">160 - 140</gadget>
<output>20</output>

<gadget id="calculator">4 + 6</gadget>
<output>10</output>

<gadget id="calculator">20 / 10</gadget>
<output>2</output>

<result>2</result>