The factory originally used 1 ton of coal, but (2/9) ton was used on the first day, and the same amount was used on the second day as on the first day. How many tons of coal are left?
工厂原有煤炭1吨，第一天用去(2/9)吨，第二天用去的和第一天同样多，还剩多少吨煤炭？
<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">1 - (2/9) - (2/9)</gadget>
<output>5/9 = around 0.555556</output>

<result>5/9 = around 0.555556</result>