There is a computer priced at 4,200 yuan. If it is sold at a 15% discount, how much will the price be reduced?
有一台电脑，定价4200元，如果八五折出售，会降价多少元？
<gadget id="calculator">85 / 100</gadget>
<output>17/20 = around 0.85</output>

<gadget id="calculator">1 - (17/20)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">4_200 * (3/20)</gadget>
<output>630</output>

<result>630</result>