Dongfang Primary School built a teaching building with an actual cost of 450,000 yuan, 10% less than planned. What was the original planned cost?
东方小学建一幢教学楼，实际造价45万元，比计划节约10%．原计划造价是多少？
<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>