题目内容
选择合理的方法进行计算.
(1)
-
+
(2)10-
-
(3)
+
-
(4)
+
+
+
(5)
+
+
.
(1)
1 |
4 |
1 |
3 |
3 |
4 |
(2)10-
7 |
12 |
5 |
12 |
(3)
5 |
8 |
3 |
4 |
1 |
3 |
(4)
1 |
4 |
11 |
15 |
3 |
4 |
4 |
15 |
(5)
7 |
15 |
19 |
21 |
2 |
21 |
考点:分数的四则混合运算,运算定律与简便运算
专题:运算顺序及法则,运算定律及简算
分析:(1)根据加法交换律进行简算;
(2)根据减法的性质进行简算;
(3)按照从左向右的顺序进行计算;
(4)根据加法交换律和结合律进行简算;
(5)根据加法结合律进行简算.
(2)根据减法的性质进行简算;
(3)按照从左向右的顺序进行计算;
(4)根据加法交换律和结合律进行简算;
(5)根据加法结合律进行简算.
解答:
解:(1)
-
+
=
+
-
=1-
=
;
(2)10-
-
=10-(
+
)
=10-1
=9;
(3)
+
-
=
-
=
;
(4)
+
+
+
=(
+
)+(
+
)
=1+1
=2;
(5)
+
+
=
+(
+
)
=
+1
=1
.
1 |
4 |
1 |
3 |
3 |
4 |
=
1 |
4 |
3 |
4 |
1 |
3 |
=1-
1 |
3 |
=
2 |
3 |
(2)10-
7 |
12 |
5 |
12 |
=10-(
7 |
12 |
5 |
12 |
=10-1
=9;
(3)
5 |
8 |
3 |
4 |
1 |
3 |
=
11 |
8 |
1 |
3 |
=
25 |
24 |
(4)
1 |
4 |
11 |
15 |
3 |
4 |
4 |
15 |
=(
1 |
4 |
3 |
4 |
11 |
15 |
4 |
15 |
=1+1
=2;
(5)
7 |
15 |
19 |
21 |
2 |
21 |
=
7 |
15 |
19 |
21 |
2 |
21 |
=
7 |
15 |
=1
7 |
15 |
点评:考查了运算定律与简便运算,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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