A pile of coal burns 12 tons in the first week, and the coal burned in the second week is 3/4 of the first week, and the pile of coal is burned in two weeks (1/3). How many tons does this pile of coal have?
一堆煤，第一周烧12吨，第二周烧的煤是第一周的(3/4)，两周共烧这堆煤的(1/3)，这堆煤有多少吨？
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">12 * (3/4)</gadget>
<output>9</output>

<gadget id="calculator">12 + 9</gadget>
<output>21</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">21 / (1/3)</gadget>
<output>63</output>

<result>63</result>