用简便方法计算（用递等式）① 392.6×192 - 知识问答

用简便方法计算（用递等式）① 392.6×192 —39260×0.92② 7.5×23+31×2.5③ 0.79×0.

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莉莉_Cc
① 392.6×192 -39260×0.92
=392.6×192-392.6×92
=392.6×(100+92)-392.6×92
=392.6×100+392.6×92-392.6×92
=39260
② 7.5×23+31×2.5
=2.5×3×23+31×2.5
=2.5×69+31×2.5
=2.5×(69+31)
=2.5×100
=250
③ 0.79×0.46＋7.9×0.24＋11.4×0.079
=0.79×0.46+0.79×2.4+1.14×0.79
=0.79×(0.46+2.4+1.14)
=0.79×4
=3.16

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