The distance from Xiaohua's home to school is 0.5km, and the distance from Xiaofang's home to school is 0.2km less than three times the distance from Xiaohua's home to school. How many kilometers will Xiaohua travel less than Xiaofang when the two go from home to school?
小华家到学校的路程是0.5km，小芳家到学校的路程比小华家到学校路程的3倍少0.2km．两个各自从家到学校，小华要比小芳少走多少千米？
<gadget id="calculator">0.5 * 3</gadget>
<output>1.5</output>

<gadget id="calculator">1.5 - 0.2 - 0.5</gadget>
<output>0.8</output>

<result>0.8</result>