A pile of coal, originally planned to burn 450 tons per day, will be burnt out in 10 days. In fact, it only takes 9 days to burn out. How many tons are burned every day? (Solved by two methods of arithmetic and ratio)
一堆煤，原计划每天烧450吨，10天烧完．实际只用9天就烧完了，每天烧多少吨？(用算术和比例两种方法解)
<gadget id="calculator">10 / 9</gadget>
<output>10/9 = around 1.111111</output>

<gadget id="calculator">450 * (10/9)</gadget>
<output>500</output>

<result>500</result>