A batch of cement, 12 tons are used, and (5/9) is left. How many tons of this batch of cement are there?
一批水泥，用去12吨，剩下(5/9)，这批水泥原来有多少吨？
<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">1 - (5/9)</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">12 / (4/9)</gadget>
<output>27</output>

<result>27</result>