There are 81 tons of grain in a certain warehouse, and (4/9) of the total has been shipped out. How many tons have been shipped out?
某仓库有粮食81吨，现已经运出了总数的(4/9)，请问运出了多少吨？
<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">81 * (4/9)</gadget>
<output>36</output>

<result>36</result>