A fraction in its simplest form, if the numerator plus 1 is equal to (2/5), if the numerator minus 1 is equal to (1/5). What is the simplest fraction.
一个最简分数，如果分子加上1等于(2/5)，如果分子减去l等于(1/5)．这个最简分数是多少．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(2/5) - (1/5)</gadget>
<output>1/5 = around 0.2</output>

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

<gadget id="calculator">(2/5) - (1/10)</gadget>
<output>3/10 = around 0.3</output>

<result>3/10 = around 0.3</result>