Lijia Hotel used 45 tons of water in October, saving 10% compared with September. How many tons of Lijia Hotel used water in September?
丽佳饭店十月用水45吨，比九月节约了10%，丽佳饭店九月用水多少吨？
<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">45 / (9/10)</gadget>
<output>50</output>

<result>50</result>