A kind of watch, the original price is 108 yuan per piece, the current price is 81 yuan, how much is it cheaper?
一种手表，原价每块108元，现价81元，便宜了百分之几？
<gadget id="calculator">108 - 81</gadget>
<output>27</output>

<gadget id="calculator">27 / 108</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>