actually, i think i figured it out by reading https://sftaxcounsel.com/demystifying-irs-form-1116-calculating-foreign-tax-credits/
3a for me is $10000 because the SALT are capped at 10000. Thus, the other deductions are state taxes that went over the 10000 limit ( I live in NYS)! Thus, are balance of my deductions i am not allowed to claim on line 2. So, i added "These are deductions beyond the $10,000 SALT limit."
