用简便方法计算下列各题(递等式,看补充!)① 0.25×(4 - 0.8)×1.25② 0.72×3.6+7.2×0.63③ 2.3×9.8+4.6

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用简便方法计算下列各题(递等式,看补充!)①0.25×(4-0.8)×1.25②0.72×3.6+7.2×0.63③2.3×9.8+4.6用简便方法计算下列各题(递等式,看补充!)①0.25×(4-0

用简便方法计算下列各题(递等式,看补充!)① 0.25×(4 - 0.8)×1.25② 0.72×3.6+7.2×0.63③ 2.3×9.8+4.6
用简便方法计算下列各题(递等式,看补充!)
① 0.25×(4 - 0.8)×1.25
② 0.72×3.6+7.2×0.63
③ 2.3×9.8+4.6

用简便方法计算下列各题(递等式,看补充!)① 0.25×(4 - 0.8)×1.25② 0.72×3.6+7.2×0.63③ 2.3×9.8+4.6
① 0.25×(4 - 0.8)×1.25
=0.25×3.2×1.25
=(0.25×4)×(0.8×1.25)
=1×1
=1
② 0.72×3.6+7.2×0.63
=7.2×0.36+7.2×0.63
=7.2×(0.36+0.63)
=7.2×0.99
=7.128
③ 2.3×9.8+4.6
=2.3×9.8+2.3×2
=2.3×(9.8+2)
=27.14