A certain township wants to build a 6km-long canal around the mountain. The first phase (1/2) of the full length was built, and the second phase built 30% of the total length. How many kilometers are left to be repaired?
某乡要修一条长6千米的环山渠，第一期修了全长的(1/2)，第二期又修了全长的30%，还剩多少千米没有修？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 - (1/2) - (3/10)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">6 * (1/5)</gadget>
<output>6/5 = around 1.2</output>

<result>6/5 = around 1.2</result>