Use 10 paper strips of the same length to form a paper tape with a length of 31 cm. If each joint overlaps by 1 cm, then how long is each paper strip in centimeters?
用10张同样长的纸条接成一条长31厘米的纸带，如果每个接头都重叠1厘米，那么每张纸条长多少厘米．
<gadget id="calculator">31 + 9</gadget>
<output>40</output>

<gadget id="calculator">40 / 10</gadget>
<output>4</output>

<result>4</result>