13.6 is 0.4 more than twice a number, find this number.
13.6比一个数的2倍多0.4，求这个数．
<gadget id="calculator">13.6 - 0.4</gadget>
<output>13.2</output>

<gadget id="calculator">13.2 / 2</gadget>
<output>6.6</output>

<result>6.6</result>