题目内容
用简便方法计算 100×
| (
|
| 17×
|
考点:分数的简便计算
专题:运算定律及简算
分析:(1)先把100分解成(101-1),再运用乘法分配律简算;
(2)(3)运用乘法分配律简算;
(4)先把17分解成(16+1),再运用乘法分配律简算.
(2)(3)运用乘法分配律简算;
(4)先把17分解成(16+1),再运用乘法分配律简算.
解答:
解:(1)100×
=(101-1)×
=101×
-1×
=100-
=99
;
(2)(
+
)×7×5
=
×7×5+
×5×7
=25+14
=39;
(3)
×
+
×
=(
+
)×
=1×
=
;
(4)17×
=(16+1)×
=16×
+1×
=3+
=3
.
100 |
101 |
=(101-1)×
100 |
101 |
=101×
100 |
101 |
100 |
101 |
=100-
100 |
101 |
=99
1 |
101 |
(2)(
5 |
7 |
2 |
5 |
=
5 |
7 |
2 |
5 |
=25+14
=39;
(3)
4 |
7 |
6 |
13 |
6 |
13 |
3 |
7 |
=(
4 |
7 |
3 |
7 |
6 |
13 |
=1×
6 |
13 |
=
6 |
13 |
(4)17×
3 |
16 |
=(16+1)×
3 |
16 |
=16×
3 |
16 |
3 |
16 |
=3+
3 |
16 |
=3
3 |
16 |
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.
练习册系列答案
相关题目