题目内容
用你喜欢的方法计算
(1)
|
(2)
| ||||||||||||||
(3)
|
(4)
|
分析:(1)根据连减的性质进行计算;
(2)根据加法交换律进行计算;
(3)先算加法,再算减法;
(4)根据连减的性质和加法结合律进行计算.
(2)根据加法交换律进行计算;
(3)先算加法,再算减法;
(4)根据连减的性质和加法结合律进行计算.
解答:解:
(1)
-
-
,
=
-(
+
),
=
-
,
=0’
(2)
+
-
,
=
-
+
,
=0+
,
=
;
(3)
+
-
,
=
-
,
=
;
(4)
-(
+
)+
,
=
-
-
+
,
=(
-
)-(
-
),
=
-0,
=
.
(1)
| 1 |
| 2 |
| 1 |
| 12 |
| 5 |
| 12 |
=
| 1 |
| 2 |
| 1 |
| 12 |
| 5 |
| 12 |
=
| 1 |
| 2 |
| 1 |
| 2 |
=0’
(2)
| 19 |
| 20 |
| 3 |
| 11 |
| 19 |
| 20 |
=
| 19 |
| 20 |
| 19 |
| 20 |
| 3 |
| 11 |
=0+
| 3 |
| 11 |
=
| 3 |
| 11 |
(3)
| 5 |
| 16 |
| 6 |
| 8 |
| 5 |
| 32 |
=
| 17 |
| 16 |
| 5 |
| 32 |
=
| 29 |
| 32 |
(4)
| 15 |
| 16 |
| 7 |
| 16 |
| 1 |
| 4 |
| 1 |
| 4 |
=
| 15 |
| 16 |
| 7 |
| 16 |
| 1 |
| 4 |
| 1 |
| 4 |
=(
| 15 |
| 16 |
| 7 |
| 16 |
| 1 |
| 4 |
| 1 |
| 4 |
=
| 1 |
| 2 |
=
| 1 |
| 2 |
点评:四则运算,先弄清运算顺序,然后再进一步计算即可,能简算的要简算.
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