The sum of two addends is 10 greater than one addend and 30 greater than the other. What is the difference between the two addends?
两个加数的和比一个加数大10，比另一个加数大30，这两个加数的差是多少．
<gadget id="calculator">30 - 10</gadget>
<output>20</output>

<result>20</result>