Li Zhuang's grain production this year increased by 10% compared to last year, and last year's grain production decreased by 10% compared to the previous year. We also know that this year's grain production is 297 tons, so how many tons of grain was produced in the previous year?
李庄今年粮食比去年增产10%，而去年比前年减产10%，又知今年粮食297吨，那么前年产粮多少吨．
<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">1 + (1/10)</gadget>
<output>11/10 = around 1.1</output>

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

<gadget id="calculator">297 / (99/100)</gadget>
<output>300</output>

<result>300</result>