题目内容
用自己喜欢的方法计算.
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分析:(1)根据加法交换律进行计算;
(2)根据乘法分配律进行计算;
(3)先算小括号里面的加法,再算乘法,最后算括号外面的加法;
(4)先算除法和乘法,再算减法;
(5)根据加法交换律和结合律进行计算;
(6)先算除法,再根据加法结合律进行计算.
(2)根据乘法分配律进行计算;
(3)先算小括号里面的加法,再算乘法,最后算括号外面的加法;
(4)先算除法和乘法,再算减法;
(5)根据加法交换律和结合律进行计算;
(6)先算除法,再根据加法结合律进行计算.
解答:解:
(1)
-
+
,
=
+
-
,
=1-
,
=
;
(2)
÷6+
×
,
=
×
+
×
,
=(
+
)×
,
=1×
,
=
;
(3)
×(
+
)+
,
=
×
+
,
=
+
,
=
;
(4)
÷
-
×
,
=
-
,
=
;
(5)
+
+
+
,
=(
+
)+(
+
),
=1+
,
=1
;
(6)
+
÷
+
,
=
+
+
,
=
+(
+
),
=
+1,
=1
.
(1)
| 20 |
| 23 |
| 1 |
| 20 |
| 3 |
| 23 |
=
| 20 |
| 23 |
| 3 |
| 23 |
| 1 |
| 20 |
=1-
| 1 |
| 20 |
=
| 19 |
| 20 |
(2)
| 2 |
| 3 |
| 1 |
| 6 |
| 1 |
| 3 |
=
| 2 |
| 3 |
| 1 |
| 6 |
| 1 |
| 6 |
| 1 |
| 3 |
=(
| 2 |
| 3 |
| 1 |
| 3 |
| 1 |
| 6 |
=1×
| 1 |
| 6 |
=
| 1 |
| 6 |
(3)
| 5 |
| 4 |
| 3 |
| 10 |
| 4 |
| 15 |
| 5 |
| 8 |
=
| 5 |
| 4 |
| 17 |
| 30 |
| 5 |
| 8 |
=
| 17 |
| 24 |
| 5 |
| 8 |
=
| 4 |
| 3 |
(4)
| 4 |
| 5 |
| 4 |
| 7 |
| 3 |
| 4 |
| 7 |
| 15 |
=
| 7 |
| 5 |
| 7 |
| 20 |
=
| 21 |
| 20 |
(5)
| 1 |
| 6 |
| 5 |
| 9 |
| 5 |
| 6 |
| 1 |
| 18 |
=(
| 1 |
| 6 |
| 5 |
| 6 |
| 5 |
| 9 |
| 1 |
| 18 |
=1+
| 11 |
| 18 |
=1
| 11 |
| 18 |
(6)
| 2 |
| 3 |
| 1 |
| 4 |
| 4 |
| 5 |
| 11 |
| 16 |
=
| 2 |
| 3 |
| 5 |
| 16 |
| 11 |
| 16 |
=
| 2 |
| 3 |
| 5 |
| 16 |
| 11 |
| 16 |
=
| 2 |
| 3 |
=1
| 2 |
| 3 |
点评:四则运算,先弄清运算顺序,然后再进一步计算,能简算的要简算.
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