题目内容
| 脱式计算.(能简算的要简算) ①
|
②
|
③[
| ||||||||||||||||||||||
④
|
⑤
|
⑥[45×(
| ||||||||||||||||||||||
⑦
|
⑧(
|
⑨
|
分析:第①②⑤⑥应用乘法分配律简便计算,使计算更加简便,第③④⑦⑧⑨题按分数、整数四则混合运算顺序计算.
解答:①
×
+
÷3,
=
×
+
×
,
=
×(
+
),
=
×1,
=
;
②
÷
+
×
,
=
×
+
×
,
=
×(
+
),
=
×1,
=
;
③[
-(
-
)]÷
,
=[
-(
-
)]×4,
=
×4,
=
,
=2
;
④
÷[(
-
)×
],
=
÷[(
-
)×
],
=
÷[
×
]
=
×6,
=3
;
⑤
×
+
×25%,
=
×
+
×
,
=
×(
+
),
=
;
⑥[45×(
+
)]÷5%,
=[45×
+45×
]×20,
=[10+15]×20,
=500;
⑦
÷(2-
)×
,
=
÷(
-
)×
,
=
×
×
,
=
;
⑧(
-
)×(
÷
),
=(
-
)×(
×
),
=
×
×
,
=
;
⑨
+(
-
)÷
,
=
+(
-
)×2,
=
+
×2,
=
+
,
=
+
,
=
.
| 1 |
| 3 |
| 4 |
| 5 |
| 1 |
| 5 |
=
| 1 |
| 3 |
| 4 |
| 5 |
| 1 |
| 5 |
| 1 |
| 3 |
=
| 1 |
| 3 |
| 4 |
| 5 |
| 1 |
| 5 |
=
| 1 |
| 3 |
=
| 1 |
| 3 |
②
| 7 |
| 9 |
| 11 |
| 5 |
| 2 |
| 9 |
| 5 |
| 11 |
=
| 7 |
| 9 |
| 5 |
| 11 |
| 2 |
| 9 |
| 5 |
| 11 |
=
| 5 |
| 11 |
| 7 |
| 9 |
| 2 |
| 9 |
=
| 5 |
| 11 |
=
| 5 |
| 11 |
③[
| 3 |
| 4 |
| 7 |
| 16 |
| 1 |
| 4 |
| 1 |
| 4 |
=[
| 12 |
| 16 |
| 7 |
| 16 |
| 4 |
| 16 |
=
| 9 |
| 16 |
=
| 9 |
| 4 |
=2
| 1 |
| 4 |
④
| 7 |
| 12 |
| 5 |
| 9 |
| 1 |
| 3 |
| 3 |
| 4 |
=
| 7 |
| 12 |
| 5 |
| 9 |
| 3 |
| 9 |
| 3 |
| 4 |
=
| 7 |
| 12 |
| 2 |
| 9 |
| 3 |
| 4 |
=
| 7 |
| 12 |
=3
| 1 |
| 2 |
⑤
| 14 |
| 25 |
| 1 |
| 4 |
| 11 |
| 25 |
=
| 14 |
| 25 |
| 1 |
| 4 |
| 11 |
| 25 |
| 1 |
| 4 |
=
| 1 |
| 4 |
| 14 |
| 25 |
| 11 |
| 25 |
=
| 1 |
| 4 |
⑥[45×(
| 2 |
| 9 |
| 1 |
| 3 |
=[45×
| 2 |
| 9 |
| 1 |
| 3 |
=[10+15]×20,
=500;
⑦
| 1 |
| 2 |
| 5 |
| 6 |
| 2 |
| 3 |
=
| 1 |
| 2 |
| 12 |
| 6 |
| 5 |
| 6 |
| 2 |
| 3 |
=
| 1 |
| 2 |
| 6 |
| 7 |
| 2 |
| 3 |
=
| 2 |
| 7 |
⑧(
| 5 |
| 8 |
| 1 |
| 4 |
| 8 |
| 9 |
| 2 |
| 3 |
=(
| 5 |
| 8 |
| 2 |
| 8 |
| 8 |
| 9 |
| 3 |
| 2 |
=
| 3 |
| 8 |
| 8 |
| 9 |
| 3 |
| 2 |
=
| 1 |
| 2 |
⑨
| 1 |
| 24 |
| 7 |
| 16 |
| 1 |
| 4 |
| 1 |
| 2 |
=
| 1 |
| 24 |
| 7 |
| 16 |
| 4 |
| 16 |
=
| 1 |
| 24 |
| 3 |
| 16 |
=
| 1 |
| 24 |
| 3 |
| 8 |
=
| 1 |
| 24 |
| 9 |
| 24 |
=
| 5 |
| 12 |
点评:此题主要考查分数、整数、小数的四则混合运算的运算顺序和应用运算定律进行简便计算.
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