题目内容
脱式计算.(能简便运算的要用简便方法算)
+
-
;
-(
-
);
-(
+
);
-(
-
).
2 |
5 |
2 |
3 |
2 |
5 |
3 |
7 |
9 |
14 |
1 |
2 |
7 |
8 |
2 |
3 |
1 |
6 |
8 |
9 |
1 |
6 |
1 |
9 |
考点:分数的四则混合运算
专题:运算顺序及法则
分析:(1)根据加法的交换律简算;
(2)先算括号里的减法,再算括号外边的减法;
(3)先算括号里的加法,再算括号外边的减法;
(4)根据减法的性质简算.
(2)先算括号里的减法,再算括号外边的减法;
(3)先算括号里的加法,再算括号外边的减法;
(4)根据减法的性质简算.
解答:
解:(1)
+
-
=
-
+
=
(2)
-(
-
)
=
-
=
(3)
-(
+
)
=
-
=
(4)
-(
-
)
=
+
-
=1-
=
2 |
5 |
2 |
3 |
2 |
5 |
=
2 |
5 |
2 |
5 |
2 |
3 |
=
2 |
3 |
(2)
3 |
7 |
9 |
14 |
1 |
2 |
=
3 |
7 |
1 |
7 |
=
2 |
7 |
(3)
7 |
8 |
2 |
3 |
1 |
6 |
=
7 |
8 |
5 |
6 |
=
1 |
24 |
(4)
8 |
9 |
1 |
6 |
1 |
9 |
=
8 |
9 |
1 |
9 |
1 |
6 |
=1-
1 |
6 |
=
5 |
6 |
点评:本题考查了分数的加减混合运算,即:只有加减同一级运算,按从左到右的顺序计算;有括号的先算括号里面的,再算括号外面的;能简算的要简算.
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