题目内容
| 用简便方法计算. (1)
|
(2)3.5-
|
(1)
-
+
,
=(
+
)-
,
=1-
,
=
;
(2)3.5-
-
,
=3.5-(
+
),
=3.5-1,
=2.5.
| 17 |
| 21 |
| 4 |
| 9 |
| 4 |
| 21 |
=(
| 17 |
| 21 |
| 4 |
| 21 |
| 4 |
| 9 |
=1-
| 4 |
| 9 |
=
| 5 |
| 9 |
(2)3.5-
| 11 |
| 16 |
| 5 |
| 16 |
=3.5-(
| 11 |
| 16 |
| 5 |
| 16 |
=3.5-1,
=2.5.
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