To build a 6km long road, (2/5) of this road was built in the first phase, and (3/10) of this road was built in the second phase, how many kilometers more were repaired in the first phase than in the second phase.
修一条长6km的道路，第一期修了这条路的(2/5)，第二期修了这条路的(3/10)，第一期比第二期多修了多少千米．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(2/5) - (3/10)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">6 * (1/10)</gadget>
<output>3/5 = around 0.6</output>

<result>3/5 = around 0.6</result>