2.1*1.1*0.54/(5.4*1.21/(5/21))=how much.
2.1*1.1*0.54/(5.4*1.21/(5/21))=多少．
<gadget id="calculator">5 / 21</gadget>
<output>5/21 = around 0.238095</output>

<gadget id="calculator">1.21 / (5/21)</gadget>
<output>5.082</output>

<gadget id="calculator">5.4 * 5.082</gadget>
<output>27.4428</output>

<gadget id="calculator">0.54 / 27.4428</gadget>
<output>0.019677</output>

<gadget id="calculator">2.1 * 1.1 * 0.019677</gadget>
<output>0.045454</output>

<result>0.045454</result>