In a subtraction formula, the sum of the minuend, the subtrahend, and the difference is 300, and the difference is 40. What is the subtrahend?
在一道减法算式里，被减数、减数、差的和是300，差是40，减数是多少．
<gadget id="calculator">300 / 2</gadget>
<output>150</output>

<gadget id="calculator">150 - 40</gadget>
<output>110</output>

<result>110</result>