There is a mobile phone shop, it takes (9/25) seconds to turn 4 screws, now there are 4500 screws, how many seconds will it take to complete.
有一家手机店，转4颗螺丝要(9/25)秒，现在有4500颗螺丝，要多少秒完成．
<gadget id="calculator">9 / 25</gadget>
<output>9/25 = around 0.36</output>

<gadget id="calculator">(9/25) / 4</gadget>
<output>9/100 = around 0.09</output>

<gadget id="calculator">(9/100) * 4_500</gadget>
<output>405</output>

<result>405</result>