For a part, the original cost of each piece was 80 yuan, but it was reduced to 50 yuan. How much is the reduction?
一种零件，原来每件成本80元，降低到50元，降低了百分之几？
<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>