Arithmetic dynamics | Base-dependent integer sequences | Number theory | Algebra

Digital root

The digital root (also repeated digital sum) of a natural number in a given radix is the (single digit) value obtained by an iterative process of summing digits, on each iteration using the result from the previous iteration to compute a digit sum. The process continues until a single-digit number is reached. For example, in base 10, the digital root of the number 12345 is 6 because the sum of the digits in the number is 1 + 2 + 3 + 4 + 5 = 15, then the addition process is repeated again for the resulting number 15, so that the sum of 1 + 5 equals 6, which is the digital root of that number. In base 10, this is equivalent to taking the remainder upon division by 9 (except when the digital root is 9, where the remainder upon division by 9 will be 0), which allows it to be used as a divisibility rule. (Wikipedia).

Video thumbnail

EnCase Computer Forensics Demo

This is a short demo of EnCase I worked up. If you are interested in some of what professional computer forensics software can do then this is for you.

From playlist digital forensics

Video thumbnail

Mathemalchemy

For more details on the Mathemalchemy project, see mathemalchemy.org

From playlist 3D printing

Video thumbnail

3D Printed Speaker

My 3D printed DIY speaker design. Tutorial: https://youtu.be/bmT21EHKQuM

From playlist 3D Printing

Video thumbnail

Create a Function: Calculus

GeoGebra Formative Assessment Resource: https://www.geogebra.org/m/grfcumbp

From playlist Calculus: Dynamic Interactives!

Video thumbnail

Continuity Definnition: Dynamic Illustration

Link: https://www.geogebra.org/m/xeA7M94B

From playlist Calculus: Dynamic Interactives!

Video thumbnail

3Doodler 2.0 Launch Video - The World's First 3D Printing Pen, Reinvented (Official)

The World's First 3D Printing Pen Just Got Even Better! Introducing the latest 3DOODLER CREATE+ https://the3doodler.com/collections/create Completely redesigned from top to bottom, and housed in a sleek aluminum casing, the new 3Doodler is also enhanced with dual-drive technology, all ai

From playlist 4D Printing And The Future Of Manufacturing

Video thumbnail

Tesla’s 3-6-9 and Vortex Math: Is this really the key to the universe?

Today, a long overdue foray into the realm of VORTEX MATHEMATICS :) 00:00 Intro 04:16 The vortex 08:10 The maths of remainders and digital roots 13:25 Demystifying the vortex 16:30 A matter of base. The 8 fingered Tesla. 19:21 Explanation why the digital root is the remainder on division

From playlist Recent videos

Video thumbnail

How To Find The Cube Root of a Large Number

This math video tutorial explains how to find the cube root of a large number without a calculator. This video contains plenty of examples and practice problems. Simplifying Super Complex Fractions: https://www.youtube.com/watch?v=Lm66pbKcP5Q Zero Factorial: https://www.youtube.com/wa

From playlist New Algebra Playlist

Video thumbnail

Square Roots and Cube Roots

This algebra video tutorial provides a basic introduction into square roots and cube roots. It explains how to determine the square roots of negative numbers, and imaginary numbers. It also explains how to determine the cube root of positive and negative numbers as well. In addition, it

From playlist New Algebra Playlist

Video thumbnail

Fast Math | Vedic Mental Math Tricks - Square Roots 02 | Don't Memorise

Learn the FASTEST and the QUICKEST way to find the SQUARE ROOT of any number(upto 5 digits). To access all videos related to Vedic Maths, enrol in our full course now: https://bit.ly/WarpMathsSquareRoots In this video, we will learn: 0:00 How to find the square root of any four-digit

From playlist Fast/Vedic/Quick/Warp Math

Video thumbnail

p-adic numbers. Part 2: p-adic powers

This is the second part of a 3-part talk on p-adic numbers for advanced high school students. It is part of a series organized by the Berkeley mathematics circle. We define the p-adic integers for p a prime, and use this to construct the field of p-adic numbers. We show how do do various

From playlist Math talks

Video thumbnail

How do we find the Cube Root of a Large Perfect Cube? | Don't Memorise

This video explains how the cube roots of large perfect cubes can be found within a few seconds! To learn more about Exponents, enroll in our course now - https://infinitylearn.com/microcourses?utm_source=youtube&utm_medium=Soical&utm_campaign=DM&utm_content=8H0l1u_xQ5o&utm_term=%7Bkeywo

From playlist Cubes and Cube roots Class 08

Video thumbnail

[ANT15] p-adic integers: a primer, and an application (part 1)

The p-adic integers are pretty easy to define, but it's far from obvious what the point of them is, or how we should even think about them. In this video, I describe them as a practical tool: a collection of number systems that are related to the usual integers Z, but where solving equatio

From playlist [ANT] An unorthodox introduction to algebraic number theory

Video thumbnail

How To Calculate Square Roots - Numerals That Changed Math Forever

There's an incredible method to extract the square root of a perfect square in your head. MIT Entrace Exam Arithmetic 1876 WayBackMachine: https://web.archive.org/web/20190404065722/https://libraries.mit.edu/archives/exhibits/exam-entrance1876/arithmetic1876.html Square root method Burnin

From playlist Mental Math Tricks

Video thumbnail

How To Find The Square Root of Large Numbers Mentally

This math video tutorial explains how to find the square root of a large number mentally. The Fibonacci Sequence and the Golden Ratio: https://www.youtube.com/watch?v=mVO2dcuR7P0 How To Simplify Cube Roots: https://www.youtube.com/watch?v=VdUNTsf14qs Double Factorials: https://www.youtu

From playlist New Algebra Playlist

Video thumbnail

Basic slide rule theory and use (Part 3): Square and Cube scales A, B, & K

The third of a series of videos explaining the basic slide rule. This video explains the A, B, and K scales and their basic uses. Basic slide rule playlist: https://www.youtube.com/playlist?list=PL_qcL_RF-ZyvJYtIr9NRXJX958d6BgdbN All my slide rule videos: https://www.youtube.com/playlis

From playlist Basic slide rule theory and use

Video thumbnail

Adding Vectors Geometrically: Dynamic Illustration

Link: https://www.geogebra.org/m/tsBer5An

From playlist Trigonometry: Dynamic Interactives!

Related pages

Hamming weight | Casting out nines | Multiplicative digital root | Iterated logarithm | Radix | Persistence of a number | Natural number | Divisibility rule | Periodic point | Fixed point (mathematics) | Digit sum | Logarithm | Arithmetic dynamics | Checksum