There are 40 poplars in the campus, willows are poplars (7/8), pagodas are willows (4/5), how many pagodas are there?
校园里有杨树40棵，柳树是杨树的(7/8)，槐树是柳树的(4/5)，槐树有多少棵？
<gadget id="calculator">7 / 8</gadget>
<output>7/8 = around 0.875</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">40 * (7/8) * (4/5)</gadget>
<output>28</output>

<result>28</result>