What is the difference between (9/10) fraction unit and (2/5) fraction unit?
(9/10)分数单位与(2/5)的分数单位相差多少．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

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

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

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