The original price of a commodity is 45 yuan, and it is sold at a 10% discount. How much is the price cut?
一种商品原价是45元，九折出售，降价了多少元．
<gadget id="calculator">90 / 100</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">1 - (9/10)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">45 * (1/10)</gadget>
<output>9/2 = around 4.5</output>

<result>9/2 = around 4.5</result>