Li Dan's family harvested 300 kilograms of corn last year, and 249 kilograms of corn the year before last.
李丹家去年收玉米300千克，前年收玉米249千克，去年比前年的玉米增产了几分之几？
<gadget id="calculator">300 - 249</gadget>
<output>51</output>

<gadget id="calculator">51 / 249</gadget>
<output>17/83 = around 0.204819</output>

<result>17/83 = around 0.204819</result>