12.5乘4.2加2.5的简便计算是？
3个回答
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12.5乘4.2加2.5的简便计算如下：
12.5×4.2+2.5
=(10+2.5)×4.2+2.5
=10×4.2+2.5×4.2+2.5
=42+2.5×(4.2+1)
=42+2.5×5.2
=42+2.5×(4+1.2)
=42+2.5×(4+3×0.4)
=42+2.5×4+3×2.5×0.4
=42+10+3×1
=42+10+3
=55
12.5×4.2+2.5
=(10+2.5)×4.2+2.5
=10×4.2+2.5×4.2+2.5
=42+2.5×(4.2+1)
=42+2.5×5.2
=42+2.5×(4+1.2)
=42+2.5×(4+3×0.4)
=42+2.5×4+3×2.5×0.4
=42+10+3×1
=42+10+3
=55
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12.5x4.2+2.5简便方法计算，
原式=10x4.2+2.5x4.2+2.5
=42+2.5x5.2
=42+2.5x（4+0.4+0.8）
=42+10+1+2
=55
原式=10x4.2+2.5x4.2+2.5
=42+2.5x5.2
=42+2.5x（4+0.4+0.8）
=42+10+1+2
=55
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12.5×4.2+2.5
=2.5×5×4.2+2.5
=2.5×21+2.5
=2.5×22
=2.5×2×11
=5×11
=55
=2.5×5×4.2+2.5
=2.5×21+2.5
=2.5×22
=2.5×2×11
=5×11
=55
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