Dig a 400-meter-long canal, and the full length (3/5) has been dug. How many meters are left to be dug?
挖一条长400米的水渠，已经挖了全长的(3/5)，还剩多少米没挖？
<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">400 * (2/5)</gadget>
<output>160</output>

<result>160</result>