A colored ribbon is cut off (1/4), and then connected to 45 meters, the result is 20% longer than the original, how many meters is the original length of the colored ribbon.
一根彩带剪掉(1/4)，再接上45米，结果比原来长20%，彩带原来长多少米．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(1/5) - (3/4)</gadget>
<output>-11/20 = around -0.55</output>

<gadget id="calculator">1 + (-11/20)</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">45 / (9/20)</gadget>
<output>100</output>

<result>100</result>