68×0.99 7.2×1.02 3.72-【1. - 知识问答

68×0.99 7.2×1.02 3.72-【1.72＋1.3】 7.7×7＋7.7＋2×7.7 简便计算.

2个回答

68×0.99
=68×(1-0.01)
=68×1-68×0.01
=68-0.68
=67.32
7.2×1.02
=7.2×(1+0.02)
=7.2×1+7.2×0.02
=7.2+0.144
=7.344
3.72-【1.72＋1.3】
=3.72-1.72-1.3
=2-1.3
=0.7
7.7×7＋7.7＋2×7.7
=7.7×（7+1+2）
=7.7×10
=77

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