A harvester harvests a wheat field. It harvests (1/8) of this wheat field on the first day, and harvests (3/10) of this wheat field on the second day. What percentage is left unharvested?
一台收割机收割一块麦田，第一天收割了这块麦田的(1/8)，第二天收割了这块麦田的(3/10)，还有几分之几没有收割？
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 - (1/8) - (3/10)</gadget>
<output>23/40 = around 0.575</output>

<result>23/40 = around 0.575</result>