The school bought 90 meters of plastic rope, cut off 36 meters and made 20 skipping ropes. According to this calculation, how many skipping ropes can be made from the remaining plastic ropes?
学校买来90米塑料绳，先剪下36米做了20跟跳绳．照这样计算，剩下的塑料绳子还可以做多少根跳绳？
<gadget id="calculator">90 - 36</gadget>
<output>54</output>

<gadget id="calculator">20 / 36</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">54 * (5/9)</gadget>
<output>30</output>

<result>30</result>