School jump rope competition. Xiaofang jumped 54 times, and Xiaofan jumped 21 times less than Xiaofang's three times. How many times did Xiaofan jump?
学校跳绳比赛．小芳跳了54下，小凡跳的比小芳的3倍少21下．小凡跳了多少下？
<gadget id="calculator">54 * 3</gadget>
<output>162</output>

<gadget id="calculator">162 - 21</gadget>
<output>141</output>

<result>141</result>