题目内容

200-199+198-197+196-195+…+4-3+2-1=
1
2
×
1
3
+
1
3
×
1
4
+
1
4
×
1
5
+…+
1
99
×
1
100
=
1.8+62=
44÷
11
10
=
2.4×5=
1
10
+
1
10
÷1=
3
8
÷
3
4
=
3.4-1
3
5
=
2-1
3
4
+
1
4
=
1
2
+
1
4
+
1
8
+…+
1
256
=
8.8×(
4
11
+
5
8
+
3
4
)=
0.75×16+
3
4
×5-
3
4
=
98÷
99
98
=
30
3
5
-(18.8+12×
3
4
)=
(1)200-199+198-197+196-195+…+4-3+2-1,
=(200-199)+(198-197)+(196-195)+…+(4-3)+(2-1),
=1×100,
=100;

(2)
1
2
×
1
3
+
1
3
×
1
4
+
1
4
×
1
5
+…+
1
99
×
1
100

=
1
2
-
1
3
+
1
3
-
1
4
+
1
4
-
1
5
+…+
1
99
-
1
100

=
1
2
-
1
100

=
49
100


(3)1.8+62=63.8;

(4)44÷
11
10

=44×
10
11

=40;

(5)2.4×5,
=(2+0.4)×5,
=2×5+0.4×5,
=10+2,
=12;

(6)1÷
1
10
+
1
10
÷1,
=1×10+
1
10

=10
1
10


(7)
3
8
÷
3
4

=
3
8
×
4
3

=
1
2


(8)3.4-1
3
5

=3.4-1.6,
=1.8;

(9)2-1
3
4
+
1
4

=2-(1
3
4
-
1
4
),
=2-1
1
2

=
1
2


(10)
1
2
+
1
4
+
1
8
+…+
1
256

=(1-
1
2
)+(
1
2
-
1
4
)+(
1
4
-
1
8
)+…+(
1
128
-
1
256
),
=1-
1
2
+
1
2
-
1
4
+
1
4
-
1
8
+…+
1
128
-
1
256

=1-
1
256

=
255
256


(11)8.8×(
4
11
+
5
8
+
3
4
),
=8.8×
4
11
+8.8×
5
8
+8.8×
3
4

=3.2+5.5+6.6,
=15.3;

(12)0.75×16+
3
4
×5-
3
4

=0.75×16+0.75×5-0.75,
=(16+5-1)×0.75,
=20×0.75,
=15;

(13)98÷
99
98

=98×
98
99

=(99-1)×
98
99

=99×
98
99
-
98
99

=98-
98
99

=97
1
99


(14)30
3
5
-(18.8+12×
3
4
),
=30.6-(18.8+9),
=30.6-27.8,
=2.8.
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