Dad used two ropes with a length of 2.17 meters to tie up the newspapers. The interface shares 0.45 meters of rope, how many meters is the rope after it is connected?
爸爸用两条长度都是2.17米的绳子接起来捆扎报纸．接口处共用去绳子0.45米，接好后的绳子有多少米？
<gadget id="calculator">2.17 * 2</gadget>
<output>4.34</output>

<gadget id="calculator">4.34 - 0.45</gadget>
<output>3.89</output>

<result>3.89</result>