A long (9/10) meter iron wire, cut off (2/5) of it for the first time, and cut off (1/10) more than the first time in the second time, leaving a few points of the full length How much?
一根长(9/10)米的铁丝，第一次剪去它的(2/5)，第二次比第一次多剪去它的(1/10)，还剩全长的几分之几？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(2/5) + (1/10)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 - (2/5) - (1/2)</gadget>
<output>1/10 = around 0.1</output>

<result>1/10 = around 0.1</result>