A product is priced at 70 yuan after a 30% discount. How much is the current price of this commodity cheaper than the original price?
一种商品打七折后售价70元．这种商品现价比原价便宜了多少元．
<gadget id="calculator">70 / 100</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">70 / (7/10)</gadget>
<output>100</output>

<gadget id="calculator">100 - 70</gadget>
<output>30</output>

<result>30</result>