regarding arrears calculation

pradeepbisht (students) (40 Points)

14 February 2018  
dear sir my client was retired in 2009 and now he is working in another co and his age is 66.now he have received an arrears for the year 2001-2009 in three instalments ,the first instalment he have received and the remaining will be receive in succeeding years .also he had no it tax details of previous years only he is having arrears details sheet how can I claim rebate u/s 89