certain brand of disinfection cabinet is now priced at 400 yuan, which is 100 yuan lower than the original price. How much is the reduction?
某种品牌的消毒柜现在售价400元，比原价降低100元，降低了多少
<gadget id="calculator">100 + 400</gadget>
<output>500</output>

<gadget id="calculator">100 / 500</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>