(X-0.1): 0.4=0.6: 1.2 then X=X=How much
(X-0.1)：0.4=0.6：1.2则X=X=多少
<gadget id="calculator">0.6 * 0.4</gadget>
<output>0.24</output>

<gadget id="calculator">0.24 / 1.2</gadget>
<output>0.2</output>

<gadget id="calculator">0.2 + 0.1</gadget>
<output>0.3</output>

<result>0.3</result>