NASA: secondary challenges
Real applications of pi in space and science, with illustrated problems and lessons for Years 9–12.
Pi Day Resources
Activities, investigations and classroom resources for secondary mathematics teachers. Pi Day is celebrated on 14 March; the next Pi Day is 14 March 2027.
Classroom resources
NASA: Years 7–8
Pi investigations and problem sets suitable for younger secondary students.
Exploratorium activities
Hands-on activities using simple materials, plus creative ways to explore pi.
Maths Is Fun: pi
A clear visual introduction to pi, circumference, diameter and approximations.
Pi Day worksheets
Printable activities on circles, radians, degrees and applications, including practice questions.
Pi in television
Person of Interest: Finch explains pi
A classroom scene in which Harold Finch introduces pi and its never-ending decimal expansion. A starting point for discussing circles, irrational numbers and infinity.
Teaching note: The scene suggests that pi contains every possible finite sequence of digits. This has not been proved; an infinite, non-repeating decimal does not by itself guarantee this property.
Activity: find your numbers in pi
Watch, search and compare
- Watch Finch’s classroom explanation above. Which claims can you investigate?
- Open Wolfram’s My Pi Day ↗ and search for your birthdate or another date of your choice. Record the exact digit sequence the tool uses and where it appears in pi.
- Compare results with classmates. Whose sequence appears earliest? Does changing the date format change the sequence and its position?
Extension: Search for your locker number or another short digit sequence using Wolfram’s Find Your Birthday in Pi exploration ↗. This includes code for searching other sequences; My Pi Day is designed for dates.
Choose a format: For 3 December 2019, use DDMMYY: 031219, or the digit list {0,3,1,2,1,9} in Wolfram. Keep leading zeros. For a locker number, use its digits, for example 123 becomes {1,2,3}.
Run the search: In the Wolfram exploration, replace the example digit list in SequencePosition with your own. Begin with the supplied number of digits and increase it if practical. Longer sequences may take much more computation.
Read the result: A pair {a,b} gives the start and end positions of a match; several pairs indicate several matches. An empty list {} means no match was found within the digits searched. The exploration’s RealDigits list includes the initial 3 as position 1, so a match starting at position a begins at decimal digit a−1.
Discuss: Finding several sequences provides examples, but does not prove that every possible sequence occurs. If a sequence is not found within the digits searched, what can you conclude?
Investigation ideas
Measure and estimate
Measure the circumference and diameter of several circular objects. Compare the ratios and discuss measurement error.
Approximate with polygons
Compare the perimeters of regular polygons inside and outside a circle. Explore how increasing the number of sides improves the estimate.
Simulate pi
For extension students, use random points in a square and its inscribed circle to estimate pi. Compare results as the sample grows.
Pi and geometric artwork
The geometric artwork used throughout MathsTeachersOnly.com was generated using my birthdate. It provides a starting point for discussing number patterns and mathematical art.
Classroom idea: assign a shape or colour to each digit, then create a design using a sequence of digits from pi.
Create Your Own Pi Artwork → Choose a starting position, colours and shading, then download the geometric design. This activity chooses a position; the Wolfram activity above searches for a sequence.
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