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Counting Rod Numerals and Mayan numerals (below) 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.

Counting Rod Numerals and Mayan numerals (below) 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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No matter. We can still teach the Turtle to write numbers in Mayan glyphs in base 20.Only the shell glyph for 0 requires any real thought.

No matter. We can still 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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[[File:TAMayanNumerals.png]]

An advantage of any of these systems is that pre-literate preschoolers can deal with them by counting before they have memorized the conventional digits. We can actually animate arithmetic in these numerals, by taking them apart into their constituents and reassembling them. Here are a few frames.

An advantage of any of these systems is that pre-literate preschoolers can deal with them by counting before they have memorized the conventional digits. We can actually animate arithmetic in these numerals, by taking them apart into their constituents and reassembling them. Here are a few frames.
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