Mock Reciprocal Table
The standard Old Babylonian reciprocal table gave the reciprocals of regular
sexagesimal numbers between 2 and 81. (A number is called regular if its
reciprocal is a terminating sexagesimal number.) Of the 50 or so known
texts, most are incomplete and many are damaged. Some of the tablets also
have a couple of extra lines at the beginning. The table below gives the
complete standard list and is taken from MCT
p11.
The standard format for each line is "igi-n-gál-bi 1/n",
where n and 1/n are the reciprocal pair of numbers.
2 30 16 3,45 45 1,20
3 20 18 3,20 48 1,15
4 15 20 3 50 1,12
5 12 24 2,30 54 1, 6,40
6 10 25 2,24 1 1
8 7,30 27 2,13,20 1, 4 56,15
9 6,40 30 2 1,12 50
10 6 32 1,52,30 1,15 48
12 5 36 1,40 1,20 45
15 4 40 1,30 1,21 44,26,40
This table is also reproduced in A. Aaboe, Episodes from the Early History
of Mathematics, Fig 1.2.
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Last modified: 7 June 2001
Duncan J. Melville
dmelville@stlawu.edu