factory produces a handicraft. Due to the adoption of a new technology, the cost of each product is now 40.5 yuan. 10% lower than the original, how much lower than the original.
一个工厂生产一种工艺品，由于采用了新工艺，现在每件产品的成本是40.5元．比原来降低了10%，比原来降低了多少元．
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 - (1/10)</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">40.5 / (9/10)</gadget>
<output>45</output>

<gadget id="calculator">45 - 40.5</gadget>
<output>4.5</output>

<result>4.5</result>