问题 解答题
计算下面各题(能简算的要简算)②5
1
5
+2
2
3
-
4
15
①1÷(1+
3
4
)
④2
1
3
×12.5×
6
7
×8
③2.8×5.6+3.4×2
4
5
-280%
77
88
×77
[1-0.8÷(
2
3
+
2
15
)]
⑧[4-(1
5
6
-0.75)÷2
8
9
]×2
2
7
×2
2
7
⑦1÷[0.5×(2
1
4
+0.25)-
1
4
]
(4
5
9
×
1
12
+31
4
9
÷12)+[8
9
16
-(3
9
16
+4
4
5
)]
(
6
7
-
7
9
)×63
答案

解①1÷(1+
3
4
)

=1÷

7
4

=

4
7

②5

1
5
+2
2
3
-
4
15

=7

13
15
-
4
15

=7

3
5

③2.8×5.6+3.4×2

4
5
-280%

=2.8×(5.6+3.4-1)

=2.8×8

=22.4;

④2

1
3
×12.5×
6
7
×8

=(

7
3
×
6
7
)×(12.5×8)

=2×100

=200;

[1-0.8÷(

2
3
+
2
15
)]

=1-0.8÷0.8

=1-1

=0;

77
88
×77

=

539
8

⑦1÷[0.5×(2

1
4
+0.25)-
1
4
]

=1÷[0.5×2.5-0.25]

=1÷[1.25-0.25]

=1÷1

=1;

⑧[4-(1

5
6
-0.75)÷2
8
9
]×2
2
7
×2
2
7

=[4-

13
12
×
9
26
2
2
7

=[4-

3
8
2
2
7

=

29
8
×2
2
7

=

58
7

(

6
7
-
7
9
)×63

=

6
7
×63-
7
9
×63

=54-49

=5;

(4

5
9
×
1
12
+31
4
9
÷12)+[8
9
16
-(3
9
16
+4
4
5
)]

=(4

5
9
+31
4
9
)×
1
12
+[8
9
16
-3
9
16
-4.8]

=36×

1
12
+[5-4.8]

=3+0.2

=3.2.

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