John O'Callaghan reached his 100th birthday, and a bit more, after a life devoted to teaching mathematics.
Born at Stockton near Newcastle in 1910, his family was poor. But John was a good student and won a scholarship to St Patrick's College, Goulburn. After teacher education, he taught in the NSW state system and also in Catholic schools.
His last last full-time teaching post was at Santa Sabina College in Strathfield and he continued coaching students well into his 80s. He was a devout Catholic and contributed to the religious lives of the parishes in Sydney where the family lived.
O'Callaghan was a great writer of letters to the Sydney Morning Herald. One of his best remembered was from December 1990, when he noted about the former British prime minister, "at one stage in John Major's career, he was rejected as a bus conductor because of his weakness in mathematics but they later made him Chancellor of the Exchequer, where, presumably, a million or two either way would not matter".
FULL OBITUARY: Master of mathematics was also a man of many letters (The Age)