题目内容
计算下列各题,能简算的要简算.
|
4-
|
(
|
|
分析:(1)把除法变成乘法,再运用乘法分配律简算;
(2)先算除法,再运用减法性质简算;
(3)先算小括号里面的除法,再算小括号里面的减法,最后算括号外的乘法;
(4)运用乘法分配律简算.
(2)先算除法,再运用减法性质简算;
(3)先算小括号里面的除法,再算小括号里面的减法,最后算括号外的乘法;
(4)运用乘法分配律简算.
解答:解:(1)
×
-
÷5,
=
×
-
×
,
=
×(
-
),
=
×1,
=
;
(2)4-
÷
-
,
=4-
-
,
=4-(
+
),
=4-1,
=3;
(3)(
-
÷2)×
,
=(
-
)×
,
=
×
,
=
;
(4)
×
+
×
,
=
×(
+
),
=
×2,
=
.
| 6 |
| 5 |
| 6 |
| 7 |
| 6 |
| 7 |
=
| 6 |
| 5 |
| 6 |
| 7 |
| 6 |
| 7 |
| 1 |
| 5 |
=
| 6 |
| 7 |
| 6 |
| 5 |
| 1 |
| 5 |
=
| 6 |
| 7 |
=
| 6 |
| 7 |
(2)4-
| 9 |
| 15 |
| 9 |
| 5 |
| 2 |
| 3 |
=4-
| 1 |
| 3 |
| 2 |
| 3 |
=4-(
| 1 |
| 3 |
| 2 |
| 3 |
=4-1,
=3;
(3)(
| 3 |
| 4 |
| 1 |
| 10 |
| 5 |
| 14 |
=(
| 3 |
| 4 |
| 1 |
| 20 |
| 5 |
| 14 |
=
| 14 |
| 20 |
| 5 |
| 14 |
=
| 1 |
| 4 |
(4)
| 3 |
| 4 |
| 5 |
| 12 |
| 5 |
| 12 |
| 5 |
| 4 |
=
| 5 |
| 12 |
| 3 |
| 4 |
| 5 |
| 4 |
=
| 5 |
| 12 |
=
| 5 |
| 6 |
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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