问题 解答题
神机妙算:
0.8×6.5-
4
5
×3.5
1
15
+
7
9
)×45
1-
8
15
÷
4
5
+
2
3
25×1.25×3299×
9
10
+
9
10
1
9
14
-
7
8
-
1
8
答案

(1)0.8×6.5-

4
5
×3.5,

=0.8×6.5-0.8×3.5,

=(6.5-3.5)×0.8,

=3×0.8,

=2.4;

(2)(

1
15
+
7
9
)×45,

=

1
15
×45+
7
9
×45,

=3+35,

=38;

(3)1-

8
15
÷
4
5
+
2
3

=1-

8
15
×
5
4
+
2
3

=1-

2
3
+
2
3

=1;

(4)25×1.25×32,

=25×1.25×8×4,

=25×4×(1.25×8),

=100×10,

=1000;

(5)99×

9
10
+
9
10

=(99+1)×

9
10

=100×

9
10

=90;

(6)1

9
14
-
7
8
-
1
8

=1

9
14
-(
7
8
+
1
8
),

=1

9
14
-1,

=

9
14

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