Mother cat and kittens go fishing. After the mother cat distributes 4 to the kittens, they each have 17 fish. How many more fish did the mother cat catch than the kittens?
猫妈妈和小猫去钓鱼．猫妈妈分给小猫4条后，它们各有17条鱼．猫妈妈比小猫多钓了几条鱼？
<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<result>8</result>