The quality of cement on the construction site is the quality of yellow sand (2/3), and 12 tons of cement and 15 tons of yellow sand are used every day. A few days later, the cement just ran out. There are still 12 tons of yellow sand, how many tons of Uehara cement was produced?
建筑工地上水泥的质量是黄沙质量的(2/3)，每天用去12吨水泥，15吨黄沙．若干天后，水泥正好用完．黄沙还有12吨，工的上原有水泥多少吨？
<gadget id="calculator">12 / 15</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

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

<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(2/3) * (1/12)</gadget>
<output>1/18 = around 0.055556</output>

<gadget id="calculator">(1/15) - (1/18)</gadget>
<output>1/90 = around 0.011111</output>

<gadget id="calculator">(4/5) / (1/90)</gadget>
<output>72</output>

<gadget id="calculator">72 * (2/3)</gadget>
<output>48</output>

<result>48</result>