小红有如图所示这样长度的三条丝带．这三条丝带的平均长度是多少？
直接写出得数．============
计算．﹣++（+） 7﹣（﹣）．
直接写得数：+=﹣=﹣=﹣=+=﹣= 1﹣=+=﹣=+=+5= 5﹣=
直接写得数．+=+=﹣= 0.25×8= 0.9×0.2=﹣=+= 10﹣= 1.25×（0.8+0.08）= 0.25×3.2=
把下面分数改写成小数，再计算++．
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= 0.25×8= 0.9×0.2=
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= 1.25×（0.8+0.08）= 0.25×3.2=
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