Find the law and calculate: 100-98+96-94+92-90+88-86+84-82...+12-10+8-6+4-2.
找规律，计算：100-98+96-94+92-90+88-86+84-82…+12-10+8-6+4-2．
<gadget id="calculator">2 * 25</gadget>
<output>50</output>

<result>50</result>