Xiaobing used his beloved "Grimm's Fairy Tales" as a charity sale in the school to support the disaster area. The original price was 40 yuan, and the charity sale price was 10 yuan cheaper than the original price. His charity sale price was 100% of the original price. How much?
小兵在学校为支援灾区举行的"爱心义卖"活动中，把自己心爱的《格林童话》作为义卖商品，原价是40元，义卖价比原价便宜了10元，他的义卖价是原价的百分之几？
<gadget id="calculator">40 - 10</gadget>
<output>30</output>

<gadget id="calculator">30 / 40</gadget>
<output>3/4 = around 0.75</output>

<result>3/4 = around 0.75</result>