After the price of a product is reduced by 10%, and the price is increased by 4 yuan, the selling price is 58 yuan. How much is the original price of this product?
一件商品降价10%后，又加价4元后的售价是58元，这件商品原价多少元？
<gadget id="calculator">58 - 4</gadget>
<output>54</output>

<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">54 / (9/10)</gadget>
<output>60</output>

<result>60</result>