<Tr> <Th_colspan="2"> Pi Day </Th> </Tr> <Tr> <Td_colspan="2"> Larry Shaw, the organizer of the first Pi Day celebration at the Exploratorium in San Francisco . </Td> </Tr> <Tr> <Th> Significance </Th> <Td> 3, 1, and 4 are the three most significant figures of π </Td> </Tr> <Tr> <Th> Celebrations </Th> <Td> Pie eating, discussions about π </Td> </Tr>

When is pie day celebrated and when is pie approximation day celebrated