A piece of clothing is cheaper than before (3/10), just 21 yuan cheaper. How much is the original price of this dress?
一件衣服比原来便宜(3/10)，正好便宜了21元．这件衣服的原价是多少元？
<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">21 / (3/10)</gadget>
<output>70</output>

<result>70</result>