题目内容
| 怎样算简便就怎样算. ①(
|
②6÷
|
③
| ||||||||||||||||||||
④
|
⑤
|
⑥1-
|
分析:①运用乘法分配律简算;
②同时运算除法,再算减法;
③先把中括号里面的计算根据减法的性质进行简算,再算括号外的除法;
④运用加法交换律和结合律简算;
⑤先把除法变成乘法,再运用乘法分配律简算;
⑥先算除法,再算减法.
②同时运算除法,再算减法;
③先把中括号里面的计算根据减法的性质进行简算,再算括号外的除法;
④运用加法交换律和结合律简算;
⑤先把除法变成乘法,再运用乘法分配律简算;
⑥先算除法,再算减法.
解答:解:①(
+
)×32,
=
×32+
×32,
=24+20,
=44;
②6÷
-
÷6,
=20-
,
=19
;
③
÷[
-(
+
)],
=
÷[
-
-
],
=
÷[
-
],
=
÷
,
=
;
④
+
+
+
,
=(
+
)+(
+
),
=1+1,
=2;
⑤
×
+
÷
,
=
×
+
×
,
=(
+
)×
,
=1×
,
=
;
⑥1-
÷
,
=1-
,
=
.
| 3 |
| 4 |
| 5 |
| 8 |
=
| 3 |
| 4 |
| 5 |
| 8 |
=24+20,
=44;
②6÷
| 3 |
| 10 |
| 3 |
| 10 |
=20-
| 1 |
| 20 |
=19
| 19 |
| 20 |
③
| 4 |
| 9 |
| 5 |
| 6 |
| 1 |
| 6 |
| 1 |
| 3 |
=
| 4 |
| 9 |
| 5 |
| 6 |
| 1 |
| 6 |
| 1 |
| 3 |
=
| 4 |
| 9 |
| 2 |
| 3 |
| 1 |
| 3 |
=
| 4 |
| 9 |
| 1 |
| 3 |
=
| 4 |
| 3 |
④
| 5 |
| 7 |
| 5 |
| 6 |
| 2 |
| 7 |
| 1 |
| 6 |
=(
| 5 |
| 7 |
| 2 |
| 7 |
| 5 |
| 6 |
| 1 |
| 6 |
=1+1,
=2;
⑤
| 4 |
| 7 |
| 5 |
| 9 |
| 3 |
| 7 |
| 9 |
| 5 |
=
| 4 |
| 7 |
| 5 |
| 9 |
| 3 |
| 7 |
| 5 |
| 9 |
=(
| 4 |
| 7 |
| 3 |
| 7 |
| 5 |
| 9 |
=1×
| 5 |
| 9 |
=
| 5 |
| 9 |
⑥1-
| 7 |
| 9 |
| 7 |
| 8 |
=1-
| 8 |
| 9 |
=
| 1 |
| 9 |
点评:此题是考查四则混合运算,要仔细观察算式的特点,灵活运用一些定律进行简便计算.
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