After subtracting how many 0.4 from 10, we are left with 4.
从10里减去多少个0.4后，还剩下4．
<gadget id="calculator">10 - 4</gadget>
<output>6</output>

<gadget id="calculator">6 / 0.4</gadget>
<output>15</output>

<result>15</result>