题目内容
(1
|
5
| ||||||||||||||||
0.5+(
|
|
分析:(1)把小数化为分数,两个括号内的同时计算,再算括号外的除法,最后算括号外的加法;
(2)先算括号内的除法和乘法,再利用减法的性质计算;
(3)把0.5化成分数,运用乘法分配律计算(
+
)×9;
(4)把小数化为分数,运用乘法交换律约分计算.
(2)先算括号内的除法和乘法,再利用减法的性质计算;
(3)把0.5化成分数,运用乘法分配律计算(
8 |
27 |
1 |
18 |
(4)把小数化为分数,运用乘法交换律约分计算.
解答:解:(1)(1
+1.25)÷
+(2.375-1
),
=(1
+1
)÷
+(2
-1
),
=
×8+
,
=23+
,
=23
;
(2)5
-(1
÷4
+
×1
),
=5
-(
×
+
×
),
=5
-(
+
),
=5
-
-
,
=5-
,
=4
;
(3)0.5+(
+
)×9+3
,
=
+
×9+
×9+3
,
=
+
+
+3
,
=(
+
)+(
+3
),
=1+6,
=7;
(4)
×(1.2+
)×1
,
=
×(
+
)×1
,
=
×
×(
+
),
=1×
,
=
.
5 |
8 |
1 |
8 |
3 |
4 |
=(1
5 |
8 |
1 |
4 |
1 |
8 |
3 |
8 |
3 |
4 |
=
23 |
8 |
5 |
8 |
=23+
5 |
8 |
=23
5 |
8 |
(2)5
5 |
12 |
7 |
8 |
1 |
2 |
3 |
4 |
1 |
5 |
=5
5 |
12 |
15 |
8 |
2 |
9 |
3 |
4 |
6 |
5 |
=5
5 |
12 |
5 |
12 |
9 |
10 |
=5
5 |
12 |
5 |
12 |
9 |
10 |
=5-
9 |
10 |
=4
1 |
10 |
(3)0.5+(
8 |
27 |
1 |
18 |
1 |
3 |
=
1 |
2 |
8 |
27 |
1 |
18 |
1 |
3 |
=
1 |
2 |
8 |
3 |
1 |
2 |
1 |
3 |
=(
1 |
2 |
1 |
2 |
8 |
3 |
1 |
3 |
=1+6,
=7;
(4)
7 |
11 |
2 |
3 |
4 |
7 |
=
7 |
11 |
6 |
5 |
2 |
3 |
4 |
7 |
=
7 |
11 |
11 |
7 |
6 |
5 |
2 |
3 |
=1×
28 |
15 |
=
28 |
15 |
点评:考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律简便计算.
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