How to pass Empty Decimal Value?

Question

I have use below two for Allocate empty value to string and pass the empty string value.

string test = "";

string test1 = string.Empty;

 

But i use decimal as empty

decimal test3 = ""; 

this is show

Cannot Implicitly convert type 'string' to 'decimal'

 and try another to refer in  online to use for fix this 

 

string test1 = string.Empty;
decimal test2 = decimal.Parse(test1);

but it shows 

Input string was not in a correct format.