There is a pile of sand, use it (1/3) on the first day, and use the rest (2/3) on the second day. At this time, the remaining sand is 40 tons less than that used on the first day. How many tons of sand to go?
有一堆沙，第一天用去它的(1/3)，第二天用去余下的(2/3)，这时，余下的沙比第一天所用的少40吨，第一天用去多少吨沙？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(2/3) * (2/3)</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">1 - (1/3) - (4/9)</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">(1/3) - (2/9)</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">40 / (1/9)</gadget>
<output>360</output>

<gadget id="calculator">360 * (1/3)</gadget>
<output>120</output>

<result>120</result>