题目内容
用你喜欢的方法计算下面各题.
+
+
-(
-
)
+
+
+
+
+
2-
-
+
+
+
.
| 1 |
| 5 |
| 5 |
| 6 |
| 2 |
| 3 |
| 7 |
| 18 |
| 5 |
| 18 |
| 1 |
| 9 |
| 5 |
| 24 |
| 1 |
| 4 |
| 2 |
| 3 |
| 3 |
| 4 |
| 4 |
| 9 |
| 1 |
| 4 |
| 2 |
| 9 |
| 2 |
| 7 |
| 3 |
| 7 |
| 3 |
| 8 |
| 2 |
| 7 |
| 1 |
| 8 |
| 5 |
| 7 |
分析:(1)运用加法结合律简算;
(2)先去掉括号,括号外是减法,去括号时把括号内的加法变成减法,减法变成加法;
(3)按照从左到右的顺序计算;
(4)运用加法结合律简算;
(5)根据连续减去两个数,等于减去这两个数的和简算;
(6)运用加法结合律简算.
(2)先去掉括号,括号外是减法,去括号时把括号内的加法变成减法,减法变成加法;
(3)按照从左到右的顺序计算;
(4)运用加法结合律简算;
(5)根据连续减去两个数,等于减去这两个数的和简算;
(6)运用加法结合律简算.
解答:解:(1)
+
+
,
=
+(
+
),
=
+
,
=
;
(2)
-(
-
),
=
-
+
,
=
+
,
=
;
(3)
+
+
,
=
+
,
=
;
(4)
+
+
+
,
=(
+
)+(
+
),
=1+
,
=1
;
(5)2-
-
,
=2-(
+
),
=2-
,
=1
;
(6)
+
+
+
,
=(
+
)+(
+
),
=
+1,
=1
.
| 1 |
| 5 |
| 5 |
| 6 |
| 2 |
| 3 |
=
| 1 |
| 5 |
| 5 |
| 6 |
| 2 |
| 3 |
=
| 1 |
| 5 |
| 3 |
| 2 |
=
| 17 |
| 10 |
(2)
| 7 |
| 18 |
| 5 |
| 18 |
| 1 |
| 9 |
=
| 7 |
| 18 |
| 5 |
| 18 |
| 1 |
| 9 |
=
| 1 |
| 9 |
| 1 |
| 9 |
=
| 2 |
| 9 |
(3)
| 5 |
| 24 |
| 1 |
| 4 |
| 2 |
| 3 |
=
| 11 |
| 24 |
| 16 |
| 24 |
=
| 9 |
| 8 |
(4)
| 3 |
| 4 |
| 4 |
| 9 |
| 1 |
| 4 |
| 2 |
| 9 |
=(
| 3 |
| 4 |
| 1 |
| 4 |
| 2 |
| 9 |
| 4 |
| 9 |
=1+
| 2 |
| 3 |
=1
| 2 |
| 3 |
(5)2-
| 2 |
| 7 |
| 3 |
| 7 |
=2-(
| 2 |
| 7 |
| 3 |
| 7 |
=2-
| 5 |
| 7 |
=1
| 2 |
| 7 |
(6)
| 3 |
| 8 |
| 2 |
| 7 |
| 1 |
| 8 |
| 5 |
| 7 |
=(
| 3 |
| 8 |
| 1 |
| 8 |
| 2 |
| 7 |
| 5 |
| 7 |
=
| 1 |
| 2 |
=1
| 1 |
| 2 |
点评:本题考查了分数的加减混合运算,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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