There is a pile of yellow sand. After using up (1/4) of this pile of yellow sand, another 12 tons were used, and 30 tons of yellow sand were used in two times. How many tons of this pile of yellow sand were there?
有一堆黄沙，用去这堆黄沙的(1/4)后，又用去12吨，两次一共用去黄沙30吨，这堆黄沙原来有多少吨？
<gadget id="calculator">30 - 12</gadget>
<output>18</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">18 / (1/4)</gadget>
<output>72</output>

<result>72</result>