There are 20 volleyballs in the school, the number of volleyballs is basketball (4/5), the number of basketballs is football (5/6), how many footballs are there?
学校有排球20个，排球的个数是篮球的(4/5)，篮球个数是足球的(5/6)，足球有多少个？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">20 / (4/5) / (5/6)</gadget>
<output>30</output>

<result>30</result>