题目内容
下面各题,能简便计算的要用简便计算
+
+
+
+
-
1-
-
-1+
.
4 |
13 |
1 |
5 |
9 |
13 |
4 |
5 |
7 |
8 |
1 |
7 |
3 |
8 |
1-
1 |
9 |
8 |
9 |
29 |
21 |
13 |
21 |
考点:运算定律与简便运算,分数的四则混合运算
专题:运算顺序及法则,运算定律及简算
分析:(1)(2)(4)运用加法交换律与结合律简算.
(3)运用减法的性质简算.
(3)运用减法的性质简算.
解答:
解:(1)
+
+
+
=(
+
)+(
+
)
=1+1
=2
(2)
+
-
=(
-
)+
=
+
=
(3)1-
-
=1-(
+
)
=1-1
=0
(4)
-1+
=(
+
)-1
=2-1
=1
4 |
13 |
1 |
5 |
9 |
13 |
4 |
5 |
=(
4 |
13 |
9 |
13 |
1 |
5 |
4 |
5 |
=1+1
=2
(2)
7 |
8 |
1 |
7 |
3 |
8 |
=(
7 |
8 |
3 |
8 |
1 |
7 |
=
1 |
2 |
1 |
7 |
=
9 |
14 |
(3)1-
1 |
9 |
8 |
9 |
=1-(
1 |
9 |
8 |
9 |
=1-1
=0
(4)
29 |
21 |
13 |
21 |
=(
29 |
21 |
13 |
21 |
=2-1
=1
点评:完成本题要注意分析式中数据,运用合适的简便方法计算.
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