No, even a gigantic salt wouldn't help because the input data is too low entropy - only 10 digits that are 0-9. Salts are only helpful to prevent rainbow table attacks by making the size of the pre-computed output space too large to fit on a drive.

The salt has to be stored in plain text in order for the verifying algorithm to compute the hash of the input and compare it, so if you have the hash you also have the salt and can brute-force old school and crack all of them in short order.