A factory used more electricity last year (1/10) than the previous year, and this year it has reduced (1/10) compared to last year. What fraction of the previous year is this year?
某工厂去年用电比前年多(1/10)，今年比去年减少(1/10)，问今年是前年的几分之几？
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 + (1/10)</gadget>
<output>11/10 = around 1.1</output>

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

<gadget id="calculator">1 * (11/10) * (9/10)</gadget>
<output>99/100 = around 0.99</output>

<result>99/100 = around 0.99</result>