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.
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.