How much is 3.6*0.5-2x=0.4.
3.6*0.5-2x=0.4多少．
<gadget id="calculator">3.6 * 0.5</gadget>
<output>1.8</output>

<gadget id="calculator">1.8 - 0.4</gadget>
<output>1.4</output>

<gadget id="calculator">1.4 / 2</gadget>
<output>0.7</output>

<result>0.7</result>