In a subtraction formula, the sum of minuend, subtrahend and difference is 8.1. Then what is the minuend.
一个减法算式中，被减数、减数、差的和是8.1．则被减数是多少．
<gadget id="calculator">8.1 / 2</gadget>
<output>4.05</output>

<result>4.05</result>