A pile of coal was brought in from the cafeteria, 12 tons were used, and 36 tons remained. What fraction of this pile of coal has been used?
食堂运来一堆煤，用去了12吨，还剩36吨．已用去这堆煤的几分之几？
<gadget id="calculator">12 + 36</gadget>
<output>48</output>

<gadget id="calculator">12 / 48</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>