The students planted 40 trees in total, 2 of which failed to survive. What fraction of the number of unsurviving trees is the number of surviving trees?
同学们一共植树40棵，未成活2棵．未成活的棵数是成活棵数的几分之几？
<gadget id="calculator">40 - 2</gadget>
<output>38</output>

<gadget id="calculator">2 / 38</gadget>
<output>1/19 = around 0.052632</output>

<result>1/19 = around 0.052632</result>