(1)923−9923+99923=
来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/05/14 19:49:58
(1)9
−99
+999
2 |
3 |
2 |
3 |
2 |
3 |
(1)9
2
3−99
2
3+999
2
3,
=(9+999-99)+(
2
3+
2
3-
2
3)
=909+
2
3,
=909
2
3;
(2)(
3
8+
1
6−
2
9)×72,
=
3
8×72+
1
6×72-
2
9×72,
=27+12-16,
=23;
(3)4.9×5
1
2+4.9+3
1
2×4.9,
=4.9×(5.5+1+3.5),
=4.9×10,
=49;
(4)9999+99992,
=9999×(1+9999),
=9999×10000,
=99990000;
(5)11×12×13-12×13-260,
=(11-1)×12×13-260,
=10×12×13-260,
=1560-260,
=1300;
(6)101×99×999+999,
=999×(101×99+1),
=999×[(100+1)×99+1];
=999×[100×99+99+1],
=999×[9900+99+1],
=999×10000,
=9990000;
(7)5
1
4×3.8+6.2×5.25,
=5.25×(3.8+6.2),
=5.25×10,
=52.5;
(8)1880×199.9-1999×187.9,
=1880×199.9-199.9×1879,
=(1880-1879)×199.9,
=1×199.9,
=199.9.
2
3−99
2
3+999
2
3,
=(9+999-99)+(
2
3+
2
3-
2
3)
=909+
2
3,
=909
2
3;
(2)(
3
8+
1
6−
2
9)×72,
=
3
8×72+
1
6×72-
2
9×72,
=27+12-16,
=23;
(3)4.9×5
1
2+4.9+3
1
2×4.9,
=4.9×(5.5+1+3.5),
=4.9×10,
=49;
(4)9999+99992,
=9999×(1+9999),
=9999×10000,
=99990000;
(5)11×12×13-12×13-260,
=(11-1)×12×13-260,
=10×12×13-260,
=1560-260,
=1300;
(6)101×99×999+999,
=999×(101×99+1),
=999×[(100+1)×99+1];
=999×[100×99+99+1],
=999×[9900+99+1],
=999×10000,
=9990000;
(7)5
1
4×3.8+6.2×5.25,
=5.25×(3.8+6.2),
=5.25×10,
=52.5;
(8)1880×199.9-1999×187.9,
=1880×199.9-199.9×1879,
=(1880-1879)×199.9,
=1×199.9,
=199.9.
(1)923−9923+99923=
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