题目内容
用自己喜欢的方法计算.
|
|
|
24×(
|
分析:(1)先算乘法,再算减法;
(2)运用乘法分配律简算;
(3)先把除法变成乘法,再运用乘法结合律简算;
(4)运用乘法分配律简算.
(2)运用乘法分配律简算;
(3)先把除法变成乘法,再运用乘法结合律简算;
(4)运用乘法分配律简算.
解答:解:(1)
-4×
,
=
-
,
=
;
(2)
×
+
×
,
=
×(
+
),
=
×1,
=
;
(3)
×
÷
,
=
×(
×
),
=
×
,
=
;
(4)24×(
+
),
=24×
+24×
,
=9+4,
=13.
| 7 |
| 8 |
| 3 |
| 16 |
=
| 7 |
| 8 |
| 6 |
| 8 |
=
| 1 |
| 8 |
(2)
| 7 |
| 18 |
| 1 |
| 4 |
| 7 |
| 18 |
| 3 |
| 4 |
=
| 7 |
| 18 |
| 1 |
| 4 |
| 3 |
| 4 |
=
| 7 |
| 18 |
=
| 7 |
| 18 |
(3)
| 5 |
| 9 |
| 14 |
| 3 |
| 28 |
| 3 |
=
| 5 |
| 9 |
| 14 |
| 3 |
| 3 |
| 28 |
=
| 5 |
| 9 |
| 1 |
| 2 |
=
| 5 |
| 18 |
(4)24×(
| 3 |
| 8 |
| 1 |
| 6 |
=24×
| 3 |
| 8 |
| 1 |
| 6 |
=9+4,
=13.
点评:运算定律是常用的简便运算的方法,要熟练掌握,灵活运用.
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