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Pi Day is celebrated on the 14th of March (3.14) around the world. Now it is also International Day of Mathematics. That's a fact that the Pi is the iconic number of mathematics, so there are plenty of websites & blogs, and zillions of activities out there to celebrate this day.

Here are some of my favorite activities I have used with the Middle School and Elementary School Students;

Classroom Posters

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Fun Facts About Pi

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Calculating Pi Like Archimedes

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Pi Day


Can't Stop

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Iconic Number



UNESCO announced Pi-Day as the International Day of Mathematics in 2019.

"Greater global awareness of mathematical sciences is vital to addressing challenges in areas such as artificial intelligence, climate change, energy, and sustainable development, and to improving the quality of life in both the developed and the developing worlds."  

Do not forget to check out the International Day of Mathematics Page for the posters!

2020 - Mathematics is Everywhere.

(The first-ever International Day of Mathematics)

2021 - Mathematics for a Better World

2022 - Mathematics Unites.

2023 - Mathematics for Everyone

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Pi TV 
Brilliant Pi Videos

Calculating π by hand: the Chudnovsky algorithm

Calculating π by hand: the Chudnovsky algorithm

For Pi Day 2018 I calculated π by hand using the Chudnovsky algorithm. k = 0 42698672/13591409 = 3.141592|751... k = 0 and k = 1 42698670.666333435968/13591408.9999997446 = 3.14159265358979|619... Watch me do the second term working out on my second channel: See me do the entire final calculation again (without a mistake) on Patreon: Proof that I did actually do it properly: This was my attempt two years ago. Look at how much hair I had! The Chudnovsky Brothers used their algorithm to be the champion pi calculators of the early 1990s: going from half a billion to four billion digits of pi. This video was filmed at Queen Mary University of London. CORRECTIONS - None yet. Let me know if you spot anything! Thanks to my Patreon supporters who enable me to spend a day doing a lot of maths by hand. Here is a random subset: Christopher Samples Sean Dempsey-Gregory Emily Dingwell Kenny Hutchings Rick de Bruijne Support my channel and I can make more videos: Music by Howard Carter Filming and editing by Trunkman Productions Audio mastering by Peter Doggart Design by Simon Wright MATT PARKER: Stand-up Mathematician Website: Maths book: Nerdy maths toys:
The Discovery That Transformed Pi

The Discovery That Transformed Pi

For thousands of years, mathematicians were calculating Pi the obvious but numerically inefficient way. Then Newton came along and changed the game. This video is sponsored by Brilliant. The first 314 people to sign up via get 20% off a yearly subscription. Happy Pi Day! References: Arndt, J., & Haenel, C. (2001). Pi-unleashed. Springer Science & Business Media — Dunham, W. (1990). Journey through genius: The great theorems of mathematics. Wiley — Borwein, J. M. (2014). The Life of π: From Archimedes to ENIAC and Beyond. In From Alexandria, Through Baghdad (pp. 531-561). Springer, Berlin, Heidelberg — Special thanks to Alex Kontorovich, Professor of Mathematics at Rutgers University, and Distinguished Visiting Professor for the Public Dissemination of Mathematics National Museum of Mathematics MoMath for being part of this Pi Day video. Special thanks to Patreon supporters: Jim Osmun, Tyson McDowell, Ludovic Robillard, jim buckmaster, fanime96, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Lyvann Ferrusca, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Pindex, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal Written by Derek Muller and Alex Kontorovich Animation by Ivy Tello Filmed by Derek Muller and Raquel Nuno Edited by Derek Muller Music by Jonny Hyman and Petr Lebedev Additional Music from "Particle Emission", "Into the Forest", "Stavselet", "Face of the Earth", "Firefly in a Fairytale" Thumbnail by Gianmarco Malandra and Karri Denise
Why do colliding blocks compute pi?

Why do colliding blocks compute pi?

Even prettier solution: Help fund future projects: An equally valuable form of support is to simply share some of the videos. Special thanks to these supporters: Home page: Many of you shared solutions, attempts, and simulations with me this last week. I loved it! You all are the best. Here are just two of my favorites. By a channel STEM cell: By Doga Kurkcuoglu: And here's a lovely interactive built by GitHub user prajwalsouza after watching this video: NY Times blog post about this problem: The original paper by Gregory Galperin: For anyone curious about if the tan(x) ≈ x approximation, being off by only a cubic error term, is actually close enough not to affect the final count, take a look at sections 9 and 10 of Galperin's paper. In short, it could break if there were some point where among the first 2N digits of pi, the last N of them were all 9's. This seems exceedingly unlikely, but it quite hard to disprove. Although I found the approach shown in this video independently, after the fact I found that Gary Antonick, who wrote the Numberplay blog referenced above, was the first to solve it this way. In some ways, I think this is the most natural approach one might take given the problem statement, as corroborated by the fact that many solutions people sent my way in this last week had this flavor. The Galperin solution you will see in the next video, though, involves a wonderfully creative perspective. If you want to contribute translated subtitles or to help review those that have already been made by others and need approval, you can click the gear icon in the video and go to subtitles/cc, then "add subtitles/cc". I really appreciate those who do this, as it helps make the lessons accessible to more people. Music by Vincent Rubinetti. Download the music on Bandcamp: Stream the music on Spotify: Timestamps 0:00 - Recap on the puzzle 1:10 - Using conservation laws 6:55 - Counting hops in our diagram 11:55 - Small angle approximations 13:04 - Summary Thanks to these viewers for their contributions to translations German: Greenst0ne Hebrew: Omer Tuchfeld ------------------ 3blue1brown is a channel about animating math, in all senses of the word animate. And you know the drill with YouTube, if you want to stay posted on new videos, subscribe: Various social media stuffs: Website: Twitter: Reddit: Instagram: Patreon: Facebook:
Why is pi here?  And why is it squared?  A geometric answer to the Basel problem