Xiao Ming takes 15 minutes to go from home to school, and Xiao Hua takes 12 minutes. How much faster is Xiao Hua than Xiao Ming?
从家到学校，小明要用15分钟，小华要用12分钟，小华的速度比小明快多少．
<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/12) - (1/15)</gadget>
<output>1/60 = around 0.016667</output>

<gadget id="calculator">(1/60) / (1/15)</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>