The original cost price of a farm tool was 320 yuan per piece, but now it is reduced to 280 yuan. How much is the cost per piece reduced?
一种农具原来每件成本价是320元，现在降低到280元，每件成本降低了百分之几？
<gadget id="calculator">320 - 280</gadget>
<output>40</output>

<gadget id="calculator">40 / 320</gadget>
<output>1/8 = around 0.125</output>

<result>1/8 = around 0.125</result>