One day, Xiaohong and Lanlan had a rope skipping competition. Xiaohong jumped 30 times at a time, a total of 17 times; Lanlan jumped 25 times at a time, a total of 20 times. Who dances more? How much?
一天，小红和兰兰比赛跳绳，小红一次跳30下，一共跳了17次；兰兰一次跳25下，一共跳了20次．她们谁跳得多？多多少呢？
<gadget id="calculator">30 * 17</gadget>
<output>510</output>

<gadget id="calculator">25 * 20</gadget>
<output>500</output>

<gadget id="calculator">510 - 500</gadget>
<output>10</output>

<result>10</result>