The fabric composition of a woolen casual coat is 20% chemical fiber, 10% rabbit fur, 30% sheep cashmere, and the rest is wool. What percentage is wool?
一件羊毛绒休闲大衣面料成分中化纤占20%，兔毛占10%，绵羊绒占30%，其余成分是羊毛，羊毛占百分之几？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 - (1/5) - (1/10) - (3/10)</gadget>
<output>2/5 = around 0.4</output>

<result>2/5 = around 0.4</result>