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速算与巧算：27+321+179，利用运算定律进行简便计算
速算与巧算：27+321+179，利用运算定律进行简便计算
计算的奥秘（速算与巧算；简便计算；运算定律；运算性质等）3/12
App06:37
App03:00
App02:49
App02:27
App06:41
App05:14
App05:33
App01:21
App02:00
App02:11
App02:52
App06:31打开App观看
速算与巧算：27+321+179，利用运算定律进行简便计算
App06:37App03:00App02:49App02:27App06:41App05:14App05:33App01:21App02:00App02:11App02:52App06:31
