6.72乘以7.53除以0.6572的简便算法应该怎么去做

再比如下面的语句,有分组运算：
SELECT * FROM local_tab a,remote_big_tab@remote b,(SELECT max(object_id) object_id FROM remote_small_tab@remote c GROUP BY c.object_type) c
WHERE b.object_id=c.object_id AND a.object_type=b.object_type;
执行计划
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Plan hash value: 2122363341
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| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | Inst |IN-OUT|
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| 0 | SELECT STATEMENT | | 2321K| 431M| 2144 (3)| 00:00:26 | | |
|* 1 | HASH JOIN | | 2321K| 431M| 2144 (3)| 00:00:26 | | |
|* 2 | HASH JOIN | | 1412 | 135K| 1836 (3)| 00:00:23 | | |
| 3 | VIEW | | 11 | 143 | 9 (12)| 00:00:01 | | |
| 4 | REMOTE | | | | | | REMOTE | R->S |
| 5 | REMOTE | REMOTE_BIG_TAB | 1479K| 119M| 1819 (2)| 00:00:22 | REMOTE | R->S |
| 6 | TABLE ACCESS FULL| LOCAL_TAB | 73985 | 7008K| 296 (1)| 00:00:04 | | |
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