When A=(1/2), B=(1/5), what is the value of (A+B)/(1-AB).
当A=(1/2)，B=(1/5)时，(A+B)/(1-AB)的值等于多少．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

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

<gadget id="calculator">(1/2) + (1/5)</gadget>
<output>7/10 = around 0.7</output>

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

<gadget id="calculator">1 - (1/10)</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">(7/10) / (9/10)</gadget>
<output>7/9 = around 0.777778</output>

<result>7/9 = around 0.777778</result>