题目内容
计算下面各题,注意使用简便算法.
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(
|
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3÷
|
6÷
|
[
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|
|
|
分析:(1)根据乘法分配律进行简算;
(2)根据乘法分配律进行简算;
(3)先算乘法,再根据加法结合律进行简算;
(4)先算除法,再算减法;
(5)按照从左向右的顺序进行计算;
(6)先算加法,再算减法,最后算乘法;
(7)根据乘法交换律和结合律进行简算;
(8)根据乘法分配律进行简算;
(9)根据乘法分配律进行简算.
(2)根据乘法分配律进行简算;
(3)先算乘法,再根据加法结合律进行简算;
(4)先算除法,再算减法;
(5)按照从左向右的顺序进行计算;
(6)先算加法,再算减法,最后算乘法;
(7)根据乘法交换律和结合律进行简算;
(8)根据乘法分配律进行简算;
(9)根据乘法分配律进行简算.
解答:解:(1)
÷
+
×
=
×
+
×
=
×(
+
)
=
;
(2)(
-
-
)×45
=
×45-
×45-
×45
=42-25-9
=17-9
=8;
(3)
+
×
+
=
+
+
=
+(
+
)
=
+2
=2
;
(4)3÷
-
÷3
=5-
=4
;
(5)6÷
÷
÷5
=30÷
÷5
=50÷5
=10;
(6)[
-(
+
)]×
=[
-
]×
=
×
=
;
(7)
×
÷
×
=(
÷
)×(
×
)
=1×
=
;
(8)
÷8+
÷
=
×
+
×
=
×(
+
)
=
;
(9)
×
-
×
=(
-
)×
=
×
=
.
| 9 |
| 10 |
| 7 |
| 4 |
| 3 |
| 7 |
| 9 |
| 10 |
=
| 9 |
| 10 |
| 4 |
| 7 |
| 3 |
| 7 |
| 9 |
| 10 |
=
| 9 |
| 10 |
| 4 |
| 7 |
| 3 |
| 7 |
=
| 9 |
| 10 |
(2)(
| 14 |
| 15 |
| 5 |
| 9 |
| 1 |
| 5 |
=
| 14 |
| 15 |
| 5 |
| 9 |
| 1 |
| 5 |
=42-25-9
=17-9
=8;
(3)
| 6 |
| 7 |
| 7 |
| 9 |
| 3 |
| 2 |
| 5 |
| 6 |
=
| 6 |
| 7 |
| 7 |
| 6 |
| 5 |
| 6 |
=
| 6 |
| 7 |
| 7 |
| 6 |
| 5 |
| 6 |
=
| 6 |
| 7 |
=2
| 6 |
| 7 |
(4)3÷
| 3 |
| 5 |
| 3 |
| 5 |
=5-
| 1 |
| 5 |
=4
| 4 |
| 5 |
(5)6÷
| 1 |
| 5 |
| 3 |
| 5 |
=30÷
| 3 |
| 5 |
=50÷5
=10;
(6)[
| 5 |
| 6 |
| 2 |
| 5 |
| 1 |
| 3 |
| 5 |
| 7 |
=[
| 5 |
| 6 |
| 11 |
| 15 |
| 5 |
| 7 |
=
| 1 |
| 10 |
| 5 |
| 7 |
=
| 1 |
| 14 |
(7)
| 5 |
| 11 |
| 1 |
| 2 |
| 5 |
| 11 |
| 1 |
| 2 |
=(
| 5 |
| 11 |
| 5 |
| 11 |
| 1 |
| 2 |
| 1 |
| 2 |
=1×
| 1 |
| 4 |
=
| 1 |
| 4 |
(8)
| 3 |
| 4 |
| 3 |
| 4 |
| 8 |
| 7 |
=
| 3 |
| 4 |
| 1 |
| 8 |
| 3 |
| 4 |
| 7 |
| 8 |
=
| 3 |
| 4 |
| 1 |
| 8 |
| 7 |
| 8 |
=
| 3 |
| 4 |
(9)
| 8 |
| 15 |
| 7 |
| 9 |
| 7 |
| 15 |
| 7 |
| 9 |
=(
| 8 |
| 15 |
| 7 |
| 15 |
| 7 |
| 9 |
=
| 1 |
| 15 |
| 7 |
| 9 |
=
| 7 |
| 135 |
点评:考查了运算定律与简便运算,四则混合运算.注意运算顺序和运算法则,灵活运用所学的运算定律简便计算.
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| ( | ||
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