The length of the swimming pool in the natatorium is 50 meters. Dad has already swam 4 rounds. How many meters has Dad swam?
游泳馆的游泳池的长是50米，爸爸已经游了4个来回，爸爸已经游了多少米？
<gadget id="calculator">2 * 4</gadget>
<output>8</output>

<gadget id="calculator">50 * 8</gadget>
<output>400</output>

<result>400</result>