Gratuity Calculation - how to calculate tonnage contract manpower Gratuity?

Hi Seniors, I have two queries on Gratuity Calculation. First one is suppose an employee is working continue for 7 year but he didn't work 240 days in a year
Since joining the organization. Then how to calculate Gratuity said employee? Last query is how to calculate tonnage contract manpower Gratuity?

Dear Sanjib,
1) If employee had worked for 7 years continuously in the system then it does not matter if he had not worked for 240 days in a year.
2) Calculation formula is the same for every gratuity calculation.