当前位置: > (1)92/3−992/3+9992/3= (2)(3/8+1/6−2/9)×72= (3)4.9×51/2+4.9+31/2×4.9= (4)9999+99992= (5)11×12×13-12×1...
题目
(1)9
2
3
−99
2
3
+999
2
3

提问时间:2020-08-31

答案
(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.
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