The original price of a product is 40 yuan, but the actual price is only 36 yuan. How much is the price reduction of this product?
一件商品原价40元，实际只卖了36元，这件商品降价百分之几？
<gadget id="calculator">40 - 36</gadget>
<output>4</output>

<gadget id="calculator">4 / 40</gadget>
<output>1/10 = around 0.1</output>

<result>1/10 = around 0.1</result>