The 42 students in the class put the papers with their student numbers on them into a box, and what is the probability that they can draw a piece of paper that is exactly their student number.
全班42名同学把写有自己学号的纸头放进一盒子内，从中抽一张纸头能抽取恰为自己学号的可能性的大小是多少．
<gadget id="calculator">1 / 42</gadget>
<output>1/42 = around 0.02381</output>

<result>1/42 = around 0.02381</result>