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−  There are several historical examples of systems for writing numbers with numerals that show 19 copies of a basic visual unit, which can be a line, a circle, a wedgeshaped cuneiform indentation, or other shapes. Some of them add in an element representing four or five single units. An advantage of any of these systems for us to consider is that preliterate preschoolers can deal with them by counting before they have memorized the conventional digits. This makes arithmetic particularly easy to demonstrate.
 +  == Turtle Art/Tutorials/Numerals == 
   
−  ==Origins of numerals==
 +  Read at https://help.sugarlabs.org/turtleart_tutorials/numerals.html 
   
−  The numerals used in various languages, living and extinct, show their origins in stroke marks or scores (cuts), like the Chinese 一二三, and the earliest forms of HinduArabicEuropean numerals. The following are Kharosthi numerals, among the earliest forms known from India. Kharosthi was written from right to left, like the source for its writing, Aramaic, and the source for all alphabetic writing, Phoenician. First we have an image, so that you don't need a Kharosthi font to view it, followed by the numerals in Unicode text.  +  The source file has been moved to [https://github.com/godiard/helpactivity/blob/master/source/turtleart_tutorials/numerals.rst GitHub] 
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−  [[File:KharosthiNumerals13.png]]
 
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−  𐩀 𐩁 𐩂
 
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−  Kharosthi numerals indicate counting on four fingers but not the thumb. The Kharosthi numeral for 4 is very similar to X, so 7 in Kharosthi can be approximated in ASCII (righttoleft, again) )))X.
 
−   
−  ==Visual numerals in Unicode==
 
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−  Here are many of the visual numerals that have made it into Unicode as characters, first as a graphic, so that you can see them even if you do not have all of the fonts needed to display them. Then I have provided them as text so that you can test which fonts you lack.
 
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−  [[File:UnicodeNumerals.png]]
 
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−  Aegean Numerals
 
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−  𐄇 𐄈 𐄉 𐄊 𐄋 𐄌 𐄍 𐄎 𐄏<br>
 
−  𐄐 𐄑 𐄒 𐄓 𐄔 𐄕 𐄖 𐄗 𐄘<br>
 
−  𐄙 𐄚 𐄛 𐄜 𐄝 𐄞 𐄟 𐄠 𐄡
 
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−  Counting Rod Numerals
 
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−  𝍠𝍡𝍢𝍣𝍤𝍥𝍦𝍧𝍨<br>
 
−  𝍩𝍪𝍫𝍬𝍭𝍮𝍯𝍰𝍱
 
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−  Cuneiform
 
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−  𒐕𒐖𒐗𒐘𒐙𒐚𒐛𒐜𒐝
 
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−  Egyptian Hieroglyphics Heqat Measure
 
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−  𓃉 𓃊 𓃋 𓃌 𓃍 𓃎 𓃏 𓃐 𓃑
 
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−  Mahjong Tiles
 
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−  🀙 🀚 🀛 🀜 🀝 🀞 🀟 🀠 🀡
 
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−  Dice are also visual, but go up only to six, with no 0.
 
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−  ⚀ ⚁ ⚂ ⚃ ⚄ ⚅
 
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−  ==Partitioning by fours and fives==
 
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−  Counting Rod Numerals show clear indications of counting on fingers up to five, then with a whole hand for five plus fingers of the second hand, as in Roman numerals.
 
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−  I II III IIII V VI VII VIII VIIII
 
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−  with the later abbreviations IV for IIII, and IX for VIIII.
 
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−  Counting Rod Numerals and Roman numerals are of the same structure as the Chinese and Japanese [[Activities/TurtleArt/Tutorials/Abacusabacuses]] (abaci?) and the Roman counting board with its little pebbles (Latin, ''calculus''/''calculi'', whence calculation and Differential and Integral [[Activities/TurtleArt/Tutorials/Kindergarten_CalculusCalculus]]).
 
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−  ==Teaching the Turtle Visual Numerals==
 
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−  Here are the second form of Counting Rod Numerals drawn by a Turtle.
 
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−  [[File:TACountingRodNumerals.png]]
 
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−  I leave the others as a programming challenge. You need to determine how to draw the elements, and how to specify the layout of elements in each numeral. For example, a program for the cuneiform wedge could go like this.
 
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−  [[File:TACuneiformWedge.png]]
 
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−  ==Mayan base 20 numerals==
 
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−  Mayan is also a candidate, notable because it is the only one of these visual numeral systems with a numeral for zero, but Mayan has not yet been added to Unicode. Mayan numerals go up to 20. This is often interpreted as counting on fingers and toes, with groupings of five for hands and feet, although we have no other evidence for how they began.
 
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−  [[File:MayanNumerals.svg]]
 
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−  We can teach the Turtle to write numbers in Mayan glyphs in base 20. Only the shell glyph for 0 requires any real thought.
 
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−  [[File:TAMayanNumerals.png]]
 
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−  ==Visual Numerals in Turtle Art==
 
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−  It should be obvious that having a Turtle write most of these numerals is fairly simple to do. We can create TA stacks for each digit in one of these systems, and display whatever sort of arithmetic we want. For example,
 
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−  [[File:TAVisualArithmetic.png]]
 
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−  We can also put these numerals on Turtle Art tiles as text. In the following illustration, each Hieroglyphic heqat measure numeral is used as a variable name with value the number it represents.
 
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−  [[File:TAHieroglyphicNumeralTiles.png]]
 
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−  [[File:TAVisualNumeralAddition]]
 
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−  ==Unicode character ranges and fonts==
 