题目内容
计算:
|
(
|
|
分析:(1)先算除法,再算加法;(2)运用乘法分配律简算;(3)把除法改为乘法,运用乘法分配律简算.
解答:解:(1)
+
÷
+
,
=
+
×
+
,
=
+
+
,
=
+
+
,
=
;
(2)(
+
-
)×72,
=
×72+
×72-
×72,
=40+60-18,
=82;
(3)
÷
+
×
,
=
×
+
×
,
=(
+
)×
,
=1×
,
=
.
| 2 |
| 9 |
| 1 |
| 8 |
| 4 |
| 5 |
| 5 |
| 8 |
=
| 2 |
| 9 |
| 1 |
| 8 |
| 5 |
| 4 |
| 5 |
| 8 |
=
| 2 |
| 9 |
| 5 |
| 32 |
| 5 |
| 8 |
=
| 64 |
| 288 |
| 45 |
| 288 |
| 180 |
| 288 |
=
| 289 |
| 288 |
(2)(
| 5 |
| 9 |
| 5 |
| 6 |
| 1 |
| 4 |
=
| 5 |
| 9 |
| 5 |
| 6 |
| 1 |
| 4 |
=40+60-18,
=82;
(3)
| 8 |
| 11 |
| 8 |
| 5 |
| 3 |
| 8 |
| 8 |
| 11 |
=
| 8 |
| 11 |
| 5 |
| 8 |
| 3 |
| 8 |
| 8 |
| 11 |
=(
| 5 |
| 8 |
| 3 |
| 8 |
| 8 |
| 11 |
=1×
| 8 |
| 11 |
=
| 8 |
| 11 |
点评:此题是考查四则混合运算的顺序与简便计算,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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