Xiaohong skipped rope 81 times, 24 times more than Xiaogang. How many times did Xiaogang jump? (First list the equations containing the unknown X, and then solve them)
小红跳绳81次，比小刚多跳了24次，小刚跳了多少次？(先列出含有未知数X的等式，再解答)
<gadget id="calculator">81 - 24</gadget>
<output>57</output>

<result>57</result>