Subtract the sum of 2 (1/8) from inside (9/10), what is the difference?
从里(9/10)减去2个(1/8)的和，差是多少？
<gadget id="calculator">9 / 10</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">2 * (1/8)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(9/10) - (1/4)</gadget>
<output>13/20 = around 0.65</output>

<result>13/20 = around 0.65</result>