The sum of two natural numbers is 50, their greatest common factor is 5, and these two numbers are not multiples, find the difference between these two numbers.
两个自然数的和是50，它们的最大公因数是5，且这两个数不是倍数关系，求这两个数的差．
<gadget id="calculator">35 - 15</gadget>
<output>20</output>

<result>20</result>