The teacher put out 5 different calculation problems on the blackboard, and asked Xiao Ming to calculate 4 of them arbitrarily. How many different choices does Xiao Gang have?
老师在黑板上出了5道不同的计算题，让小明任意计算其中的4题，小刚一共有多少种不同的选法．
<gadget id="calculator">5 * 4 * 3 * 2</gadget>
<output>120</output>

<gadget id="calculator">4 * 3 * 2 * 1</gadget>
<output>24</output>

<gadget id="calculator">120 / 24</gadget>
<output>5</output>

<result>5</result>