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The reckoning board, also called a memory board or hole board, could be used on its own as a basic counting device or used with an abacus for engineering. There were two types of reckoning board. The older type was a simple 10 × 10 grid of holes. A peg would be inserted into a hole and moved along, starting from the top and working downwards. It was used as a memory aid when counting certain units. For every sack of grain or bar of steel, the peg would be moved forward and after a day or a week, the total number counted could be seen. The more advanced type had columns of holes, with the columns indicating place value. ==See also== *Cribbage board *Abacus *Sand table 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Reckoning board」の詳細全文を読む スポンサード リンク
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