A school built a new teaching building. The original plan was to invest 500,000 yuan, but the actual savings were 10% compared to the plan. How much is the actual investment?
某校建一座新教学楼，原计划投资50万元，实际比计划节约10%．实际投资多少万元？
<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">50 * (9/10)</gadget>
<output>45</output>

<result>45</result>