来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/09/04 14:24:41
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.
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