When the quotient of 4.2/0.8 is 5, what is the remainder
4.2/0.8的商是5时，余数是多少
<gadget id="calculator">0.8 * 5</gadget>
<output>4</output>

<gadget id="calculator">4.2 - 4</gadget>
<output>0.2</output>

<result>0.2</result>