Uncle Dink poured a glass of water, drank it (9/10), and poured it in again (7/10). What percentage of the glass is the water in the glass now?
丁克舅舅倒了一杯水，喝掉了(9/10)，又倒入了(7/10)．现在杯中的水占杯子的几分之几？
<gadget id="calculator">9 / 10</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">1 - (9/10)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">7 / 10</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">(1/10) + (7/10)</gadget>
<output>4/5 = around 0.8</output>

<result>4/5 = around 0.8</result>