After increasing 0.8 by how much, the number obtained is 5 times it.
把0.8增加多少后，所得的数是它的5倍．
<gadget id="calculator">0.8 * 5</gadget>
<output>4</output>

<gadget id="calculator">4 - 0.8</gadget>
<output>3.2</output>

<result>3.2</result>