∵A={x|

6

x-3

∈Z，x∈N}

∴x=9     

6

x-3

=1

x=6      

6

x-3

=2

x=5       

6

x-3

=3

x=4       

6

x-3

=6

x=2       

6

x-3

=-6

x=1         

6

x-3

=-3

x=0        

6

x-3

=-2

∴A中元素个数为7

故答案为：7