题目内容
计算下列各题.(能简算的要简算)
|
15×(
|
| ||||||||||||||||||||
[3-(
|
(
|
|
分析:(1)先算除法,再算乘法;
(2)根据乘法分配律进行计算;
(3)根据乘法分配律进行计算;
(4)先算小括号里面的减法,再算中括号里面的减法,最后算除法;
(5)先算加法,再算除法;
(6)根据乘法分配律进行计算.
(2)根据乘法分配律进行计算;
(3)根据乘法分配律进行计算;
(4)先算小括号里面的减法,再算中括号里面的减法,最后算除法;
(5)先算加法,再算除法;
(6)根据乘法分配律进行计算.
解答:解:(1)
÷6×
,
=
×
,
=
;
(2)15×(
+
),
=15×
+15×
,
=10+9,
=19;
(3)
÷8+
×
,
=
×
+
×
,
=(
+
)×
,
=1×
,
=
;
(4)[3-(
-
)]÷
,
=[3-
]÷
,
=
÷
,
=
;
(5)(
+
)÷
,
=
÷
,
=
;
(6)
÷
+
×
,
=
×
+
×
,!
=(
+
)×
,
=1×
,
=
.
| 3 |
| 10 |
| 2 |
| 3 |
=
| 1 |
| 20 |
| 2 |
| 3 |
=
| 1 |
| 30 |
(2)15×(
| 2 |
| 3 |
| 3 |
| 5 |
=15×
| 2 |
| 3 |
| 3 |
| 5 |
=10+9,
=19;
(3)
| 2 |
| 3 |
| 1 |
| 3 |
| 1 |
| 8 |
=
| 2 |
| 3 |
| 1 |
| 8 |
| 1 |
| 3 |
| 1 |
| 8 |
=(
| 2 |
| 3 |
| 1 |
| 3 |
| 1 |
| 8 |
=1×
| 1 |
| 8 |
=
| 1 |
| 8 |
(4)[3-(
| 3 |
| 4 |
| 3 |
| 8 |
| 9 |
| 2 |
=[3-
| 3 |
| 8 |
| 9 |
| 2 |
=
| 21 |
| 8 |
| 9 |
| 2 |
=
| 7 |
| 12 |
(5)(
| 4 |
| 5 |
| 3 |
| 10 |
| 3 |
| 10 |
=
| 11 |
| 10 |
| 3 |
| 10 |
=
| 11 |
| 3 |
(6)
| 5 |
| 12 |
| 31 |
| 30 |
| 30 |
| 31 |
| 7 |
| 12 |
=
| 5 |
| 12 |
| 30 |
| 31 |
| 30 |
| 31 |
| 7 |
| 12 |
=(
| 5 |
| 12 |
| 7 |
| 12 |
| 30 |
| 31 |
=1×
| 30 |
| 31 |
=
| 30 |
| 31 |
点评:完成本题要注意分析式中数据,运用合适的简便方法计算.
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