题目内容
计算下面各题,能简便计算的要简便计算.
+
-
-
-
+
-
-
+
+
+
.
5 |
6 |
5 |
8 |
8 |
9 |
2 |
3 |
3 |
4 |
4 |
7 |
5 |
3 |
5 |
9 |
5 |
6 |
3 |
2 |
2 |
7 |
5 |
7 |
5 |
8 |
8 |
5 |
3 |
8 |
2 |
5 |
分析:第(1)(2)(3)(4)题,属于异分母分数加减法计算,需要先通分,再计算;
第(5)题,运用减法的性质简算;
第(6)题,运用加法交换律和结合律简算.
第(5)题,运用减法的性质简算;
第(6)题,运用加法交换律和结合律简算.
解答:解:(1)
+
,
=
+
,
=
;
(2)
-
,
=
-
,
=
;
(3)
-
,
=
-
,
=
;
(4)
-
+
,
=
-
+
,
=
;
(5)
-
-
,
=
-(
+
),
=
-1,
=
;
(6)
+
+
+
,
=(
+
)+(
+
),
=1+2,
=3.
5 |
6 |
5 |
8 |
=
20 |
24 |
15 |
24 |
=
35 |
24 |
(2)
8 |
9 |
2 |
3 |
=
8 |
9 |
6 |
9 |
=
2 |
9 |
(3)
3 |
4 |
4 |
7 |
=
21 |
28 |
16 |
28 |
=
5 |
28 |
(4)
5 |
3 |
5 |
9 |
5 |
6 |
=
30 |
18 |
10 |
18 |
15 |
18 |
=
35 |
18 |
(5)
3 |
2 |
2 |
7 |
5 |
7 |
=
3 |
2 |
2 |
7 |
5 |
7 |
=
3 |
2 |
=
1 |
2 |
(6)
5 |
8 |
8 |
5 |
3 |
8 |
2 |
5 |
=(
5 |
8 |
3 |
8 |
8 |
5 |
2 |
5 |
=1+2,
=3.
点评:此题考查了分数的加减法计算,以及运用运算定律简算的能力.
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