Answer
The last surviving child of King George V and Queen Mary was Prince Henry, Duke of Gloucester. He was born on 31 March 1900 and died on 10 June 1974. He was the youngest of five children, and his older siblings were Edward VIII, who abdicated in 1936; Albert, who became King George VI; Mary, who married Henry Lascelles, 6th Earl of Harewood; and George, who died in infancy.