In the love charity sale organized by the school, Xiaogang sold his beloved "General History of China" as a charity sale commodity. The original price of "General History of China" was 80 yuan, and his charity sale price was 50 yuan, which was 100% less than the original price. How much?
在学校组织的爱心义卖活动中，小刚把自己心爱的《中国通史》作为义卖商品卖出，《中国通史》的原价是80元，他的义卖价是50元，义卖价比原价少百分之几？
<gadget id="calculator">80 - 50</gadget>
<output>30</output>

<gadget id="calculator">30 / 80</gadget>
<output>3/8 = around 0.375</output>

<result>3/8 = around 0.375</result>