Counting Rods - Rod Numerals

Rod Numerals

Rod numerals are a positional numeral system made from shapes of counting rods. Positive numbers are written as they are and the negative numbers are written with a slant bar at the last digit. The vertical bar in the horizontal forms 6-9 is drawn shorter to have the same character height.

A circle (〇) is used for 0. Many historians think it was imported from Indian numerals by Gautama Siddha in 718, but some think it was created from the Chinese text space filler "□".

In the 13th century, Southern Song mathematicians changed digits for 4, 5, and 9 to reduce strokes. The new horizontal forms eventually transformed into Suzhou numerals. Japanese continued to use the traditional forms.

Positive numbers (traditional)
0 1 2 3 4 5 6 7 8 9
Vertical
Horizontal
Negative numbers (traditional)
-0 -1 -2 -3 -4 -5 -6 -7 -8 -9
Vertical
Positive numbers (Southern Song)
0 1 2 3 4 5 6 7 8 9
Vertical
Horizontal Counting rod h7 num.png

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