An antiviral drug sold by a pharmacy raises the price by 100% without permission when the market is in short supply. After investigation by the price department, the required price increase can only be 10% of the original price.
某药店经营的抗病毒药品，在市场紧缺的情况下私自提价100%，物价部门查处后，要求提价的幅度只能是原价的10%，则该药品现在需降价多少．
<gadget id="calculator">100 / 100</gadget>
<output>1</output>

<gadget id="calculator">1 + 1</gadget>
<output>2</output>

<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 + (1/10)</gadget>
<output>11/10 = around 1.1</output>

<gadget id="calculator">2 - (11/10)</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">(9/10) / 2</gadget>
<output>9/20 = around 0.45</output>

<result>9/20 = around 0.45</result>