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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