indexOf is not a function

Question

I' am currently working with the following code. In the console it's throwing

Uncaught TypeError: TotalAccountBalance.indexOf is not a function

I don't know what else to do. Searching didn't help much.

var CurrentPreservedBalance, CurrentGeneralAccountBalance, TotalAccountBalance;
    CurrentPreservedBalance = '20.56';
    CurrentGeneralAccountBalance = '20.56';
    if( CurrentPreservedBalance && CurrentGeneralAccountBalance ){
        TotalAccountBalance = +CurrentPreservedBalance + +CurrentGeneralAccountBalance;
        console.log( TotalAccountBalance.indexOf('.') );
    } else {
        $('#total-fnpf-account-balance').val('$0.00');
        $('#total-account-balance').val('$0.00');
    }

Answer 1

indexOf() is a method of Strings, not Numbers.

console.log( TotalAccountBalance.toString().indexOf('.') );