A set of mathematics self-study books, the current price is 160 yuan, which is 40 yuan lower than the original price, so the current price is the original price.
一套数学自学丛书，现价是160元，比原价降低了40元，则现价是原价的多少．
<gadget id="calculator">160 + 40</gadget>
<output>200</output>

<gadget id="calculator">160 / 200</gadget>
<output>4/5 = around 0.8</output>

<result>4/5 = around 0.8</result>