## The Standard Algorithm of Addition: Part 3

In the blog “Standard Algorithm of Addition: Part 1,” we learned how to set up addition problems in a vertical format so that we can manually calculate their sum. We also learned the mathematical terms for the components of arithmetic expressions of additions. In the blog “Standard Algorithm of Addition: Part 2,” I used a {visual model} to explain the concept behind this fundamental algorithm using green square blocks and blue rods to represent the addends. In this blog, I will show you how the standard algorithm works {number model}.

First we set up the arithmetic expression in a vertical format (A). Now we will first focus on the ones column and work our way from right to left (B). We mentally add the digits in the ones (9+7=16). Note the sum is greater than 9. This sum is equivalent to 1 unit of ten (blue rod) and 6 units of ones (green squares) (C). I write the digit for the 6 units of one in the ones column under the underline (D). I place the 1 digit of ten at the top of the tens column (E).

Working our way from right to left, we move to the tens column (F). We add the digits in this column noting that we are actually adding multiples of ten (G). Since the sum is not greater than 99, we simply write the sum of the digits in the tens column underneath the underline (H). Therefore, the sum of the addends, 29 and 47, is 76 (I).  It is the most common technique of addition taught to math students, but it is not the only one.  We’ll look at some other addition algorithms in future blogs.

John Tenniel (1820-1914) was a British illustrator, graphic humorist and political cartoonist. He achieved considerable fame as the illustrator of Alice. Tenniel drew ninety-two drawings for Lewis Carroll’s “Alice’s Adventures in Wonderland” (London: Macmillan, 1865) and “Through the Looking Glass” (London: Macmillan, 1871). There is an illustration to the ninth chapter of Through the Looking Glass and excerpt that touches upon the topic of recent blogs.

Illustration to the ninth chapter of “Through the Looking Glass” by John Tenniel. Wood-engraving by the Dalziels.

“Manners are not taught in lessons,” said Alice. “Lessons teach you to do sums, and things of that sort.”
“Can you do Addition?” the White Queen asked. “What’s one and one and one and one and one and one and one and one and one and one?”

“I don’t know,” said Alice. “I lost count.”
“She can’t do Addition,” the Red Queen interrupted..

The .pdf copy of this book was made available to the public by Lenny de Rooy at her website, Lenny’s Alice in Wonderland Site.

## The Mechanical Arithmetic of the Pascaline

Blaise Pascal (1623-1662) is known today as a brilliant French mathematician, physicist, inventor, writer and Christian philosopher. In 1642, he attempted to help his father, a tax collector, deal with the repetitive arithmetic calculations that were part of the task of reorganizing the tax revenues of the French province of Upper Normandy. He was thus motivated to develop and invent the only functional calculator of the 17th century, known as the Pascaline, in 1645. It could add and (indirectly) subtract two numbers. It could also multiply and divide by repetition. In 1649 a royal privilege, by Louis XIV of France, gave him the exclusivity of the design and manufacturing of calculating machines in France. He designed the only functional calculator of the 17th century.

As far as I can tell, nine Pascalines still exist today. Four of them are on display at the National Conservatory of Arts and Crafts (CNAM) museum in Paris, France. There is also an interesting video that explains how this fascinating mechanical calculator worked. I encourage you to watch, learn and explore this intriguing bit of math history and technology.

In order to use language to communicate math concepts and skills concisely {language model}, we must learn the terminology and vocabulary of mathematics so that we can express ourselves accurately. Lets begin by learning the English math words associated with the fundamental skill of addition and its associated numerical expressions {number model}.

An arithmetic expression is a mathematical statement consisting of real numbers and mathematical operations. There are no variables in an arithmetic expression.

The plus sign is the mathematical symbol representing the operation of addition.

The equal sign tells us that the the math statement on its left is the same value (equal) to the math statement on the right

This arithmetic equation is a mathematical statement which uses the equal sign to state that the arithmetic expression on the left (the sum of the two addends) is equal to the statement on the right of the equal sign (the sum).

Each language and culture uses its own terminology and vocabulary to represent these components of addition. Learning these words and their meaning is one important way the world of language arts and world of mathematics intersects.  One of the most basic tools I use to assess whether a student I am tutoring is fluent in the use of math vocabulary is through the use of flashcards.  I usually just ask the student to identify the component of the expression or equation highlighted in red.  Many times, there is more than one acceptable answer, as you will see in future blogs.

## Addition and the Ishango Bone

In today’s blog, we are going to start a steady and cumulative process of exploring the concepts and techniques of mathematics in an evolutionary way. You will soon realize that even the most basic concepts can be seen in different and interesting ways. As always, and whenever possible, I’ll point you to some interesting places, events and people in the history of mathematics.  Lets start with the concept of addition. Addition evolved out of a very fundamental desire to count and know the quantity of similar objects we have.

Suppose we begin with two sets of objects (1). Set A consists of six elements (blue discs) and Set B has three elements (green discs). These two sets have no elements in common. The intersection of sets A and B is the empty set. Thus, they are referred to as disjoint sets. The union of sets A and B consists of both the six blue discs and the three green discs. In the Hindu/Arabic number system, there are numbers that are used to represent the quantities of discs in each set (2). In this case, it is the numbers “6” and “3.” The union of two disjointed sets is a visual way of representing the sum of two numbers. The addition symbol (+) is used to represent the operation of addition in a mathematical expression or equation. The sum of these two numbers is equivalent to counting the number of blue and green discs in the union of two sets (3).  In this case, six plus three is equal to nine.  One should note that counting is nothing more than the repeated addition of 1 to generate a set of natural numbers.

In 1960, a Belgian geologist, Jean de Heinzelin de Braucourt (1920-1998) was exploring an area of Africa near the headwaters of the Nile River at Lake Edwards, called Ishango. At the time, the area was part of the Belgian Congo. He discovered a large number of tools, artifacts, and human remains.  In the world of archeology, there have been numerous discoveries of prehistoric animal bones that have notches carved into them. These artifacts are generally known as tallies or tally sticks. Some of these notched bones have proven to be more interesting to the mathematical community than others. One of these interesting bones was discovered at Ishango by Jean de Heinzelin de Braucourt . Today, this artifact is referred to as the Ishango bone.  It is considered the second oldest mathematical object. However, its exact purpose has yet to be determined.

The Ishango bone is currently on display at the Royal Institute of Natural Sciences in Brussels, Belgium.  There, you will find a Flash-based website on the Ishango archeological site, which will give you a detailed explanation of the bone’s markings and its possible uses. Explore this site and you will find out how far back the history of mathematics stretches.