计算下面各题.
0.25×4.78×4
32×1.25+1.25×68
10.4-9.6×0.5
3.12+3.12×99.
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解:(1)0.25×4.78×4,
=(0.25×4)×4.78,
=1×4.78,
=4.78;
(2)32×1.25+1.25×68,
=(32+68)×1.25,
=100×1.25,
=125;
(3)10.4-9.6×0.5,
=10.4-4.8,
=5.6;
(4)3.12+3.12×99,
=3.12×(1+99),
=3.12×100,
=312.
解析分析:(1)运用乘法交换律简算;
(2)(4)运用乘法分配律简算;
(3)先算乘法,再算减法.
点评:此题考查了小数的四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算律简便计算.