已知长方形的宽为4厘米，那么阴影部分的面积是多少？
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口算显身手！= = = = == = = =
计算下面各题．40××608×27×．
用颜色涂出每种图形的．并说一说每种图形的的个数一样多吗？为什么？
请观察并计算下列各题，你发现了什么？×= ×= == ﹣= ﹣=﹣= ﹣=
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×60
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．并说一说每种图形的
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