# Changes

,  23:06, 19 July 2011
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There are several historical examples of systems for writing numbers with numerals that show 1-9 copies of a basic visual unit, which can be a line, a circle, a wedge-shaped cuneiform indentation, or other shapes. An advantage of any of these systems for us to consider is that pre-literate preschoolers can deal with them by counting before they have memorized the conventional digits. This makes arithmetic particularly easy to demonstrate.
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There are several historical examples of systems for writing numbers with numerals that show 1-9 copies of a basic visual unit, which can be a line, a circle, a wedge-shaped 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 pre-literate preschoolers can deal with them by counting before they have memorized the conventional digits. This makes arithmetic particularly easy to demonstrate.

==Origins of numerals==

==Origins of numerals==
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𐩀 𐩁 𐩂

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 could be written (right-to-left, again) ))X.
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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 (right-to-left, again) )))X.

==Visual numerals in Unicode==

==Visual numerals in Unicode==
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Counting Rod Numerals and Roman numerals are of the same structure as the Chinese and Japanese [[Activities/TurtleArt/Tutorials/Abacus|abacuses]] (abaci?) and the Roman counting board with its little pebbles (Latin, ''calculus''/''calculi'', whence calculation and Differential and Integral [[Activities/TurtleArt/Tutorials/Kindergarten_Calculus|Calculus]]).

Counting Rod Numerals and Roman numerals are of the same structure as the Chinese and Japanese [[Activities/TurtleArt/Tutorials/Abacus|abacuses]] (abaci?) and the Roman counting board with its little pebbles (Latin, ''calculus''/''calculi'', whence calculation and Differential and Integral [[Activities/TurtleArt/Tutorials/Kindergarten_Calculus|Calculus]]).
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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]]

==Mayan base 20 numerals==

==Mayan base 20 numerals==
1,009

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