问题 解答题
用简便方法计算.
5
9
+
3
11
+
5
9
+
8
11
7
18
×
1
4
+
3
4
×
7
18
7
15
-(
7
15
-
3
7
)+
4
7
8×(4-3.75)÷0.1
7
12
-
5
18
)×12×18
(15.6+9.744÷2.4)×0.5.
答案

(1)

5
9
+
3
11
+
5
9
+
8
11

=(

5
9
+
5
9
)+(
3
11
+
8
11
),

=

10
9
+1,

=2

1
9

(2)

7
18
×
1
4
+
3
4
×
7
18

=(

1
4
+
3
4
)×
7
18

=1×

7
18

=

7
18

(3)

7
15
-(
7
15
-
3
7
)+
4
7

=

7
15
-
7
15
+(
3
7
+
4
7
),

=0+1,

=1;

(4)8×(4-3.75)÷0.1

=8×0.25÷0.1,

=2÷0.1,

=20;

(5)(

7
12
-
5
18
)×12×18

=

7
12
×12×18-
5
18
×12×18,

=126-60,

=66;

(6)(15.6+9.744÷2.4)×0.5

=(15.6+4.06)×0.5,

=19.66×0.5,

=9.83.

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