Zerah Colburn

American mental calculator

Zerah Colburn (born Cabot, Vermont, 1804; died 1839) was a child prodigy. He became famous when he was a little boy because he could do unbelievably difficult sums very easily. However, he wasted his talent and never became a useful mathematician.

Zerah’s father was a carpenter. He and his wife had six children, and they had very little money.

When he was five he started to go to school. After six weeks his father heard him doing multiplication sums. His father asked him what 13 times 97 was. The boy immediately said “1261”.

His father took him to Boston to show him to famous people. They asked the boy questions: what is 1449 times 1449? The boy said “2,099,601”. Someone else asked him how many seconds there were in 2000 years. He said “63,072,000,000”.

His father looked for rich people who would pay for the boy’s education. In Boston $5000 was raised so that he did not have to be shown off in public all the time. Nevertheless, his father took him to Europe. In London people asked him more questions, e.g. is 4,294,967,297 a prime number? The boy said “No, it can be divided by 641”.

People wanted the boy to explain how he did these calculations, but he could not say how he did it. He became famous. Napoleon was going to meet him, but he lost the Battle of Waterloo and was not able to make the visit. He went to school in Paris and then in London, but by the time he was 15 people were not interested in helping him any more. He joined a touring group of actors and got the part of Richard III in the play by Shakespeare. He met William Rowan Hamilton who was also a prodigy and who did become a famous mathematician. Zerah soon got fed up with mathematics and became a Methodist minister. He taught languages at Norwich University in Vermont. He wrote an autobiography in which he tried to explain how he did his calculations.

When he died most people had forgotten about him.

His nephew, also named Zerah Colburn, was a famous locomotive designer.


Zerah, like his father, had 12 fingers and 12 toes.

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