In the ball game, Xiao Ming has already made 15 shots, and the total number of shots will be three times the number of shots.
在拍球比赛中，小明已经拍了15个，再拍多少个，拍的总数就是已拍的3倍．
<gadget id="calculator">15 * 2</gadget>
<output>30</output>

<result>30</result>