Use a tractor to plow a field, plow (1/10) on the first day, and plow (1/9) on the second day, how much more is left over than the second day?
用拖拉机耕一块地，第一天耕了(1/10)，第二天耕了(1/9)，剩下的比第二天多多少？
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 / 9</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">(1/10) + (1/9)</gadget>
<output>19/90 = around 0.211111</output>

<gadget id="calculator">1 - (19/90) - (1/9)</gadget>
<output>61/90 = around 0.677778</output>

<result>61/90 = around 0.677778</result>