Arithmetic | Error detection and correction

Casting out nines

Casting out nines is any of three arithmetical procedures: * Adding the decimal digits of a positive whole number, while optionally ignoring any 9s or digits which sum to a multiple of 9. The result of this procedure is a number which is smaller than the original whenever the original has more than one digit, leaves the same remainder as the original after division by nine, and may be obtained from the original by subtracting a multiple of 9 from it. The name of the procedure derives from this latter property. * Repeated application of this procedure to the results obtained from previous applications until a single-digit number is obtained. This single-digit number is called the "digital root" of the original. If a number is divisible by 9, its digital root is 9. Otherwise, its digital root is the remainder it leaves after being divided by 9. * A sanity test in which the above-mentioned procedures are used to check for errors in arithmetical calculations. The test is carried out by applying the same sequence of arithmetical operations to the digital roots of the operands as are applied to the operands themselves. If no mistakes are made in the calculations, the digital roots of the two resultants should be the same. If they are different, therefore, one or more mistakes must have been made in the calculations. (Wikipedia).

Video thumbnail

Lockdown Friday 20th August

Recorded with https://screencast-o-matic.com

From playlist Lockdown 2021

Video thumbnail

Game of Nine Solution

Solution to my 'Game of Nine' video: http://youtu.be/ue4Baa8Mhn8 Each player takes it in turns to pick a number, the first to pick three numbers that add up to 15 wins. With this simulation you don't even need a friend! http://gammahoo.de/gameofnine Thanks to GammahooX for making it

From playlist My Maths Videos

Video thumbnail

Awesome Number Pattern 9

A number pattern that results in numbers with 8 for a digit

From playlist Number Patterns

Video thumbnail

Ex 2: Determine Factors of a Number

This is the second of three videos that provides examples of how to determine the factors of a number using a numbers prime factors. Search Video Library at http://www.mathispower4u.wordpress.com

From playlist Factors and Prime Factorization

Video thumbnail

Awesome Number Pattern 7

A fun number pattern built from the number 987654321

From playlist Number Patterns

Video thumbnail

Using the Combinations Formula by Hand Example

Please Subscribe here, thank you!!! https://goo.gl/JQ8Nys Using the Combinations Formula by Hand Example

From playlist Statistics

Video thumbnail

Q216

Check out my site & social media 😃 T-shirts: https://teespring.com/stores/blackpenredpen 😃 https://blackpenredpen.com 😃 https://twitter.com/blackpenredpen 😃 https://www.instagram.com/blackpenredpen/ 😃 https://www.patreon.com/blackpenredpen 😃 Wix: http://wixstats.com/?a=25754&c=124&s1= bl

From playlist Intro to Series, calculus 2

Video thumbnail

03 Placing numbers on a number line #38

In this video we place rational and irrational numbers on the number line

From playlist Skill 13 Attempt 2

Video thumbnail

How to check math multiplication - cast out nines trick

Casting out nines is a fast and easy method of making sure your math multiplication calculations are correct. This trick involves adding the digits of each number and reducing each to a single digit, then comparing the end result with the answer. To donate to the tecmath channel: https:/

From playlist tecmath math

Video thumbnail

Math division - cast out nines trick

Casting out nines is a fast and easy method of making sure your math division calculations are correct. This trick is fast, easy, and accurate! To donate to the tecmath channel: https://paypal.me/tecmath?locale.x=en_AU To donate to the tecmath channel: https://paypal.me/tecmath?locale.x=e

From playlist tecmath math

Video thumbnail

Check your math addition - casting out nines trick

Casting out nines is a fast and easy method of making sure your math addition calculations are correct. This trick involves adding the digits of each number and reducing each to a single digit, then comparing the end result with the answer. To donate to the tecmath channel: https://paypa

From playlist tecmath math

Video thumbnail

Re-writing the Code of Life: CRISPR Systems and Applications of Gene Editing

Gene editing with CRISPR technology is transforming biology. Understanding the underlying chemical mechanisms of RNA-guided DNA and RNA cleavage provides a foundation for both conceptual advances and technology development. Professor Jennifer Doudna ForMemRS discusses how bacterial CRISPR

From playlist Latest talks and lectures

Video thumbnail

David Bikard - Studying And Fighting Pathogenic Bacteria...

Studying And Fighting Pathogenic Bacteria with the Help of Crispr Cas systems have emerged has a powerful biotechnological tool. The Cas9 protein is a RNA-guided nuclease that can be easily reprogrammed to target any sequence of interest. Our work focuses on the development

From playlist Cellular and Molecular Biotechnology

Video thumbnail

Greek Physics: Calculating the distance to the Sun and Moon

This video looks at the method of Aristarchus for determining the distance to the Sun and Moon. This video takes inspiration from the book 'To Explain the World' by Steven Weinberg, which provides an excellent commentary on the discovery of modern science. You can help support this channe

From playlist Pen and Paper

Video thumbnail

THIS & THAT #61 tubalcain mrpete foundry patterns castings

Make a Drill Press Vise From Castings Tips #433 pt1 tubalcain https://studio.youtube.com/video/r7jgrvkADUU/edit What Was Casting Specialties? Tips #444 STRUCK tubalcain https://www.youtube.com/watch?v=u3HI6UqSHqw SUBSCRIBE if you enjoy the content! I have tubalcain tee shirts available.

From playlist THIS & THAT by tubalcain

Video thumbnail

Year 12/AS Pure Chapter 10.2 (Trigonometric Identities and Equations)

In this video we take a look at how the CAST diagram can be used to find exact values of trigonometric ratios, and later we see how can use the identities sin²θ + cos²θ ≡ 1 and tanθ = sinθ/cosθ to simplify various trigonometric expressions. This lesson is meant as preparation for Exercis

From playlist Year 12/AS Edexcel (8MA0) Mathematics: FULL COURSE

Video thumbnail

THE BASICS: Light-Value-Edges-Contrast- An Introduction

Marc discusses the concepts of Light, Value, Edges, and Contrasts in an opening introduction to deeper learning on these topics in drawing. Master these concepts and ideas intellectually, before moving forward to practicing these elements in drawing! The forms used can be bought at NASCO

From playlist THE BASICS

Video thumbnail

Awesome Number Pattern 14

Create numbers with nine distinct digits

From playlist Number Patterns

Video thumbnail

A Model of Tumor Heterogeneity Identifies Metastatic Disease Progression - S. Knott - 1/14/16

Full Title: A Model of Tumor Heterogeneity Identifies Novel Drivers of Metastatic Disease Progression Bioinformatics Research Symposium Beckman Institute Auditorium Thursday, January 14, 2016

From playlist Bioinformatics Research Symposium

Related pages

Signal processing | Greek numerals | Coefficient | Summation | Check digit | Avicenna | Iamblichus | Product (mathematics) | Nicomachus | Digit sum | Checksum | Division (mathematics) | Multiplication | Addition | Integer | Divisor | Subtraction | Digital root | Quotient | Fibonacci | Remainder