Concatenate syntax

Hi,

I am using this 

Test=cancatenate(format(divide([a],[b]), "#.0%" & Unichar(10)), (" (" & if [a]=0, "0")& "/" & if ([b]=0, "0",[b])& ")"))

using this syntex i am getting parenthesis for all except zero. PLease see the picture. I want to remove Parenthesis from 0 only and keep parenthesis to all value. I have tried to write the syntex like below.

Test=cancatenate(format(divide([a],[b]), "#.0%" & Unichar(10)),  if format([a]=0, "0","(#,#)")& "/" & if ([b]=0, "0",format([b],"(#,#")))

but results coming like (123)/(456) and with zero it didnt show () sign. 

I want my result (123/456) and when any row comes 0,it will show only 0.

Please help me to figure out this syntex.

Thanks in advance.