If (1/2) m is cut off from a ribbon, (3/5) of the full length remains, what is the total length of this ribbon in dm?
一条丝带剪去(1/2)m，还剩下全长的(3/5)，这条丝带全长多少dm．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(1/2) / (2/5)</gadget>
<output>5/4 = around 1.25</output>

<result>5/4 = around 1.25</result>