Hi @vishwa1979 you were missing an else statement in your formula as well as Endif to state the end of the IF. In addtion you set the data type to be numeric I changed the data type to string and it worked. However if you want the result to be numeric then the arguement after the Then will not require to be in quotes e.g. "0.5" would need to be 0.5. String data needs to be quotes numeric data does not to be in quotes.
@JosephSerpis has solved the error in your workflow, but I did want to make a best-practice recommendation, that you consider replacing the large IF statement with a Text Input Tool, then Joining on the two columns used as a conditional check to obtain the corresponding calculation value. (Don't forget to Union to get remaining records). Here is a sample of that with the Text Input Tool preconstructed based on shared data: