How many digits in pi?

Because Pi is known to be an irrational number it means that the digits never end or repeat in any known way. But calculating the digits of Pi has proven to be an fascination for mathematicians throughout history. Some spent their lives calculating the digits of Pi, but until computers, less than 1,000 digits had been calculated. In 1949, a computer calculated 2,000 digits and the race was on. Millions of digits have been calculated, with the record held (as of September 1999) by a supercomputer at the University of Tokyo that calculated 206,158,430,000 digits. (first 1,000 digits).

However, learning 3.141, is all that is necessary.

But you can go on and on, to infinity, and never find the exact circumference of a circle. I have only memorized 205 digits of pi; and yes I do use it to find the circumference of a circle.