The number of sixth-grade students in Xiaoying Primary School decreased by 10% last year compared to the previous year, and this year increased by 20% compared to last year. Will it increase or decrease this year compared to the previous year, and by what percentage?
小营小学六年级学生人数去年比前年减10%，今年比去年增加20%，则今年比前年增加还是减少了，增加或减少了百分之几？
<gadget id="calculator">10 / 100</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">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">1 * (9/10) * (6/5)</gadget>
<output>27/25 = around 1.08</output>

<gadget id="calculator">(27/25) - 1</gadget>
<output>2/25 = around 0.08</output>

<gadget id="calculator">(2/25) / 1</gadget>
<output>2/25 = around 0.08</output>

<result>2/25 = around 0.08</result>