Xiaohong bought a picture album at a stationery store at a discounted price of 35% off, and it cost 13.91 yuan. How much cheaper is this picture album?
小红在文具店按六五折的优惠价格买了一本画册，用去13.91元，买这本画册便宜了多少元？
<gadget id="calculator">65 / 100</gadget>
<output>13/20 = around 0.65</output>

<gadget id="calculator">13.91 / (13/20)</gadget>
<output>21.4</output>

<gadget id="calculator">21.4 - 13.91</gadget>
<output>7.49</output>

<result>7.49</result>