The factory rushed to make 756 pieces of emergency tools for earthquake relief. The original plan was to do 6 pieces per person per day, and 18 people were sent to complete the task. In order to speed up the progress, 3 more people were added. How many days can the task be completed in advance?
工厂为抗震抢险赶制756件抢险工具．原计划每人每天做6件，派18个人来完成，为加快进度，又增加了3人，可提前几天完成任务？
<gadget id="calculator">6 * 18</gadget>
<output>108</output>

<gadget id="calculator">756 / 108</gadget>
<output>7</output>

<gadget id="calculator">18 + 3</gadget>
<output>21</output>

<gadget id="calculator">6 * 21</gadget>
<output>126</output>

<gadget id="calculator">756 / 126</gadget>
<output>6</output>

<gadget id="calculator">7 - 6</gadget>
<output>1</output>

<result>1</result>