Having a large family has helped strengthen the marriage of Haji Kassim Sultan, 98, and Hajah Tuminah Haji Siraj, 88.

The couple have been married for 73 years. They have 13 children, one of whom died young, 32 grandchildren and 36 great-grandchildren.

Having many children has helped to bond the family, says Madam Tuminah. The couple say they enjoy having a big and close-knit family, even though they had to be frugal while raising the children.

Mr Kassim used to work from 7am to 10pm as a typewriting instructor and also repaired and serviced typewriters in his spare time.

His homemaker wife worked as a seamstress whenever she could and used the leftover fabric to make clothes for their children.

The family lived in a kampung in Bukit Timah, near a mosque where Mr Kassim has volunteered for 66 years. Today, at least nine other family members volunteer at Masjid Al-Huda, where one of the couple's sons, Haji Azman Haji Kassim, 57, serves as chairman.

Mr Azman recalls how he and his siblings always played together. One of the games they enjoyed was badminton - their father marked out the lines on a field in the kampung to indicate the parameters of a badminton court.

The children looked forward to their father returning home at night with fruit for supper. Mr Azman recalls that six durians were enough for the family as a treat.

Today, all the children are grown-up and married.

Mr Kassim and Madam Tuminah live with their 62-year-old daughter and her husband in an HDB flat in Jurong.

Mr Kassim points out that focusing solely on the children is not enough for a happy marriage.

"You must be good to your wife," he says, adding that he used to go to the market with his wife every Sunday. "We also laugh together."