In a subtraction formula, the sum of the minuend, the subtrahend and the difference is 100, and the difference is 10 less than the subtrahend, so what is the difference?
在一道减法算式里，被减数、减数和差三个数的和是100，差比减数少10，那么差是多少？
<gadget id="calculator">10 + 10 + 100</gadget>
<output>120</output>

<gadget id="calculator">1 + 1 + 1 + 1</gadget>
<output>4</output>

<gadget id="calculator">120 / 4</gadget>
<output>30</output>

<gadget id="calculator">30 - 10</gadget>
<output>20</output>

<result>20</result>