The worker uncle makes a batch of parts. After (5/9), there are still 900 parts left. How many parts are there in total?
工人叔叔做一批零件，做了(5/9)后，还剩900个，这批零件一共多少个？
<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">1 - (5/9)</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">900 / (4/9)</gadget>
<output>2_025</output>

<result>2_025</result>