题目内容
用简便方法计算下面各题.
|
|
| 15×
|
(1)
×
+
×
=(
+
)×
=1×
=
;
(2)
×7+11÷
=
×7+11×
=
×(7+11)
=
×18
=10;
(3)
÷7+
×
=
×
+
×
=(
+
)×
=1×
=
;
(4)15×
-
=(15-1)×
=14×
=12.
2 |
7 |
4 |
5 |
5 |
7 |
4 |
5 |
=(
2 |
7 |
5 |
7 |
4 |
5 |
=1×
4 |
5 |
=
4 |
5 |
(2)
5 |
9 |
9 |
5 |
=
5 |
9 |
5 |
9 |
=
5 |
9 |
=
5 |
9 |
=10;
(3)
8 |
13 |
1 |
7 |
5 |
13 |
=
8 |
13 |
1 |
7 |
1 |
7 |
5 |
13 |
=(
8 |
13 |
5 |
13 |
1 |
7 |
=1×
1 |
7 |
=
1 |
7 |
(4)15×
6 |
7 |
6 |
7 |
=(15-1)×
6 |
7 |
=14×
6 |
7 |
=12.
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