题目内容
| 用自己喜欢的方法计算 21÷(
|
|
|
(1)21÷(
÷
),
=21÷(
×
),
=21÷
,
=21×
,
=28;
(2)
×
÷
×
,
=
÷
×
×
,
=1×
×
,
=
;
(3)
+
÷
,
=
+
×
,
=
+
,
=
.
| 2 |
| 5 |
| 8 |
| 15 |
=21÷(
| 2 |
| 5 |
| 15 |
| 8 |
=21÷
| 3 |
| 4 |
=21×
| 4 |
| 3 |
=28;
(2)
| 3 |
| 4 |
| 1 |
| 5 |
| 3 |
| 4 |
| 3 |
| 5 |
=
| 3 |
| 4 |
| 3 |
| 4 |
| 1 |
| 5 |
| 3 |
| 5 |
=1×
| 1 |
| 5 |
| 3 |
| 5 |
=
| 3 |
| 25 |
(3)
| 7 |
| 15 |
| 8 |
| 15 |
| 4 |
| 3 |
=
| 7 |
| 15 |
| 8 |
| 15 |
| 3 |
| 4 |
=
| 7 |
| 15 |
| 2 |
| 5 |
=
| 13 |
| 15 |
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