面方格纸上画出一个周长是10厘米的长方形，并求出它的面积．（一格表示1平方厘米）
1﹣= ．
1+3= ．
= ．
口算 55+37= 80﹣26= 1400﹣800= 2+210= 9+300= 82+0= 1﹣= += ﹣= ．
口算我最棒.+=+=﹣=﹣=+= 1+=﹣0.2=+0.3=+= 1﹣+=﹣﹣=++=
= ．
+3= ．
= ．
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﹣
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+
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﹣
﹣
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= 1+
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﹣0.2=
+0.3=
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= 1﹣
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