Minuend, subtrahend, the sum of the difference is 180, the difference is 75, what is the subtrahend.
被减数，减数，差的和是180，差是75，减数是多少．
<gadget id="calculator">180 / 2</gadget>
<output>90</output>

<gadget id="calculator">90 - 75</gadget>
<output>15</output>

<result>15</result>