Li Ming bought a pair of jeans at a discounted price of 25% in the shopping mall, which cost 90 yuan. How much cheaper are these jeans than the original price?
李明在商场按七五折的优惠价格买了一条牛仔裤，用去90元，这种牛仔裤比原价便宜了多少元？
<gadget id="calculator">75 / 100</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">90 / (3/4)</gadget>
<output>120</output>

<gadget id="calculator">120 - 90</gadget>
<output>30</output>

<result>30</result>