There is a pile of yellow sand on the construction site, the first time (1/7) is used, and the second time (1/6), what fraction is left?
工地上有一堆黄沙，第一次用去(1/7)，第二次用去(1/6)，还剩下几分之几？
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 - (1/7) - (1/6)</gadget>
<output>29/42 = around 0.690476</output>

<result>29/42 = around 0.690476</result>