# How did the check pattern help with financial computations?

[ Wikipedia : ] The check pattern is also used in many areas other than textile styles, for example: on a board used by the mediaeval Exchequer to perform financial computations [...]

[ Etymonline : ] Government financial sense began under the Norman kings of England[,] and refers to a cloth divided in squares that covered a table on which accounts of revenue were reckoned with counters, and which apparently reminded people of a chess board.

Why did medieval officials use material with the Check Pattern for calculating?

• There's no question in this question. If this is a work-in-progress, you really need to start with at least the base question before adding more information. If this was posted in error, it would be helpful if you deleted it. – user22859 Mar 29 '18 at 6:23
• -1 as a quick Wikipedia search would have answered the question! en.m.wikipedia.org/wiki/Exchequer – TheHonRose Mar 29 '18 at 9:45
• I'm not fully sure i understand the how. Wikipedia asserts the function, but I don't have a procedural understanding - just some guesses. – Mark C. Wallace Mar 29 '18 at 11:09

Surprisingly difficult to find a good image to illustrate this. I think the description in Wikipedia is as clear as any I've read:

The Exchequer was named after a table used to perform calculations for taxes and goods in the medieval period.[11] According to the Dialogue concerning the Exchequer,[12] an early medieval work describing the practice of the Exchequer, the table was large, 10 feet by 5 feet with a raised edge or "lip" on all sides of about the height of four fingers to ensure that nothing fell off it, upon which counters were placed representing various values. The name Exchequer referred to the resemblance of the table to a chess board (French: échiquier) as it was covered by a black cloth bearing green stripes of about the breadth of a human hand, in a chequer-pattern. The spaces represented pounds, shillings and pence. Wikipedia

Alternatively,

The Exchequer’s rather unusual name was derived from the chequered cloth on which the confrontational audit process took place between the powerful Barons of the upper Exchequer and the hapless accountants summoned before them, who were regularly interrogated about the state of their accounts. The cloth was used to visually record the sums of money that were demanded and received, and an accountant was only discharged of their debt on the provision of evidence – a writ authorising expenditure on behalf of the Crown, or a wooden tally denoting that a payment had been made into the lower Exchequer. history.blog.uk

"Before decimalisation, the pound was divided into 20 shillings and each shilling into 12 pence, making 240 pence to the pound." Pound Sterling

Even addition and subtraction can be challenging in a pre-decimal pound. If I have a debt of 31L, and I pay 7s2p every year, how long will it take to pay off the debt?

I don't have a clear source/citation, but I have always assumed that the checkered pattern served as a form of place value. When there are 13p in a square, remove them all and place 1s in the next square; if that square now hoas 2os, remove and place 1L in the next, etc.

The eminent Mr. Geerkens points out: (I'm repeating here only because comments are ephemeral, and the substance is, I think, important enough to be part of the answer.)

As this is occurring in roughly the two centuries before the widespread adoption of double-entry bookkeeping, it might be a sort of precursor to that - with Assets and Liabilities in two separate sets of columns. The Missing Dollar riddle is a perfect example of how easily one's intuition can be fooled without a rigorous accounting method in place. Two quick points: 1) Accrual accounting and the Income Statement are 19th century developments. Everything is Cash accounting before that. 2) Modern Balance Sheet divides the RHS into Liabilities and Equities - but note Equities really means Claims. Originally the RHS distinction was between debt equities and ownership equities.

I have half a mind to experiment with the missing dollar problem on a virtual exchequer.

• As this is occurring in roughly the two centuries before the widespread adoption of double-entry bookkeeping, it might be a sort of precursor to that - with Assets and Liabilities in two separate sets of columns. The Missing Dollar riddle is a perfect example of how easily one's intuition can be fooled without a rigorous accounting method in place. – Pieter Geerkens Mar 29 '18 at 11:36
• Splendid comment; wish I could upvote more. – Mark C. Wallace Mar 29 '18 at 11:46
• Run with it if you wish - I have just started a new career and will not have time to properly write up answers for a few months. – Pieter Geerkens Mar 29 '18 at 11:48
• @MarkCWallace "Even addition and subtraction can be challenging in a pre-decimal pound." Not really, if you grow up with it! If you have 99 cents and someone gives you 1 cent, you know you have a dollar. If as a child 4 kind relatives gave me 10 shillings, 5 shillings and two amounts of 2 shillings 6 pence, I did not need to be a mathematical genius (I'm not!) to know I was the proud possessor of £1. Guineas (£1 +1shilling) were more sneaky - 20 guineas was actually £21. Still used by auction houses I believe - regarded as "posher"! But not rocket science. – TheHonRose Mar 30 '18 at 1:35
• @TheHonRose: Exactly! It's just a place-value number system where the rightmost two places are respectively base-20 and base-12 instead of base-10 like the rest. – Pieter Geerkens Apr 28 '18 at 22:36