1. 直接写出得数。
$2.5×0.6×0.4 = $
$1.25×0.7×0.8 = $
$0.26×0.2×50 = $
$0.5×0.75×4 = $
$2.5×0.6×0.4 = $
$1.25×0.7×0.8 = $
$0.26×0.2×50 = $
$0.5×0.75×4 = $
答案
0.6 0.7 2.6 1.5
2. 计算下面各题。你认为怎样简便就怎样算。
$49×0.125×8$
$0.4×63×2.5$
$0.34×101$
$4.86×99$
$49×0.125×8$
$0.4×63×2.5$
$0.34×101$
$4.86×99$
答案
49 63 34.34 481.14
解析
$49×0.125×8$
$=49×(0.125×8)$
$=49×1$
$=49$
$0.4×63×2.5$
$=0.4×2.5×63$
$=1×63$
$=63$
$0.34×101$
$=0.34×(100+1)$
$=0.34×100+0.34×1$
$=34+0.34$
$=34.34$
$4.86×99$
$=4.86×(100-1)$
$=4.86×100-4.86×1$
$=486-4.86$
$=481.14$
$=49×(0.125×8)$
$=49×1$
$=49$
$0.4×63×2.5$
$=0.4×2.5×63$
$=1×63$
$=63$
$0.34×101$
$=0.34×(100+1)$
$=0.34×100+0.34×1$
$=34+0.34$
$=34.34$
$4.86×99$
$=4.86×(100-1)$
$=4.86×100-4.86×1$
$=486-4.86$
$=481.14$
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