Pi Approximation Day: 7 other mathematical symbols you should know about

On Pi Approximation Day, here are 7 other mathematical symbols you should know about

Pi Approximation Day: 7 other mathematical symbols you should know about
On Pi Approximation Day, here are 7 other mathematical symbols you should know about.

By India Today Web Desk: Pi is the simplest possible ratio of the simplest possible figure. The ratio between the distance all the way around a circle, to its largest distance across is the ratio known as Pi, which remains constant for all perfect circles irrespective of their size.

The ratio can be represented by 22/7 which results in approximately3.14. What can be a more perfect day to celebrate and talk about Pi than today?


In reality, the ratio of Pi extends much further than 3.14 indefinitely which is puzzlingly random. For mathematicians and engineers, this ratio used to be big trouble, and repeatedly mentioning it in equations used to be really incommodious. That’s when the idea of signs and symbols came into being for numerals.

In fact, 22/7 was the first number ever to get a symbol assigned to it. William Jones was the one who first associated the Greek Letter Pi () with the ratio in 1706, which was later popularised by Leonard Euler who brought it to common use in 1737.

Since then, a lot of symbols and signs have come up assigned to numerals whose values tend to remain constant and operations.

Pi Day vs Pi Approximation Day

Both Pi Day and Pi Approximation Day are celebration of the mathematical constant Pi ().

Pi Day is celebrated on March 14 as the date is 3-14 in the US date format, which is similar to the approximate value of Pi 3.14.

Pi Approximation Day is often celebrated on July 22 as it is written as 22/7 in the English or European date format which tallies with its approximate value of Pi -- 22/7.

Today on Pi Approximation Day, let’s check out a few unconventional symbols used in Mathematics:

1. Phi ()- The Golden Ratio/Golden Mean/Divine Proportion

This ratio can be referred to as “The Perfect Matchmaker”. Just think about it, having two completely different fields such as Arts and Mathematics date each other is no feeble feat.

Phi is a mathematical ratio (approx 1.618) that appears very often in nature reflecting a sense of grandeur, beauty, and aesthetics to the human eye.

2. Tensor Product ()- Vector Operator

Unlike the previous symbol, this one is an operator (i.e, a symbol representing an operation between two or more numbers, like addition, subtraction, multiplication, or division).

This one is different from a normal product as it essentially used for the product of two vector quantities. It’s applicable in quantum mechanics for defining the state of a quantum system.


3. Conditional Probability (|)- Probability operator

This is again a mathematical operator, and its usage in mathematics is different from how it’s used in computer science where it’s used as BITWISE OR.

In mathematics, its usage can most commonly be seen in Bayes Theorem Formula. Represented as P(A | B), it furnishes the probability of Event A provided that Event B happened.

Real-life applications include assessment of risk management.

4. Equivalence ()- Identical To

I am pretty sure that any grown adult today has at least once in their lifetime came across “equals to” represented by “=”. What most people don’t know however is that “equals to” isn’t just one operator but a family in itself, with family members such as Congruency, Similarity, Parallel, and much more.

Equivalence is another such member of this mathematical parentage. For understanding equivalence, an example is in order.

Both a book and tuition are useful for a child for studying, but that doesn’t mean they are “equal to” each other. Instead, we can refer to them as being in equivalence in the context of their usefulness to children.

5. Euler’s Number (e)- Mathematical Constant

Euler’s Number named after the legendary mathematician Leonhard Euler. Euler’s Number, although not that mainstream as Pi, is used in mathematics as much as Pi.


Calculus, Differential Equations, Trigonometry, Statistics, Complex Analysis, and Discrete Mathematics is just to name a few fields that would never have been, had Euler’s Number never existed.

Its value equals to 2.71828 (approx).

6. Capital Pi ()- Product of Series

Capital Pi is actually only namely similar to the Pi we celebrate today. In fact, it’s more similar to Sigma () than to Pi.

Just as Sigma is the sum of all the values in a range of series, Capital Pi is the Product of all such values in a range of series.

7. Epsilon ()- Near Zero Positive Value

Imagine having zero by not having zero, crazy right? Epsilon is essentially the closest one can be to nothingness without being nothing.

In Mathematics, epsilon is defined as an infinitesimally small positive value that approaches zero but is not zero.

Epsilon’s most adhered uses are in Calculus and its different sub-branches like Limits and Continuity etc.


We have just scratched the surface when it comes to lesser-known symbols in mathematics because most of the generally known mathematics constitutes just 10% of the entire mathematics.


And still, a lot of research is going on in mathematics to make it more conforming to its various applications in Physics, Finance, and other fields.

One thing is for sure though; Pi will always retain a “celebrity-like” status within our mathematical minds. It is destined to always remain constant unless we hop onto another universe that has a different curvature of space-time, who knows maybe things may come “full circle” soon.

-Article by Rohit Manglik, CEO, EduGorilla

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