certain electrical appliance company produced 4.5 million mobile phones last year, an increase of 500,000 units compared to the plan, and how much was the increase?
某电器股份有限公司去年生产移动电话450万部，比计划增产50万部，增产了百分之几？
<gadget id="calculator">450 - 50</gadget>
<output>400</output>

<gadget id="calculator">50 / 400</gadget>
<output>1/8 = around 0.125</output>

<result>1/8 = around 0.125</result>