Zhong Ming's crayon used to be 8 cm long. After 45 mm is used up, how many centimeters is the crayon now?
钟鸣的蜡笔原来长8厘米，用去45毫米后，现在这支蜡笔有多少厘米？
<gadget id="calculator">8 - 4.5</gadget>
<output>3.5</output>

<result>3.5</result>