The Nephite monetary system was a one, two, four, seven system. “The Nephite system was a peculiarly efficient one. The selections of 1, 2, 4, and 7 for the values of the larger coins seems particularly wise in what intelligent people who were willing to have ‘altered their reckoning … in every generation’ (Alma 11:4) might be expected to work out…”
“If the major coins had denominations 1, 2, 4, and 8, then three coins, (1, 2, and 4) would be required for a purchase costing 7 of the basic units, while only one, the (7) would be required in the “1-2-4-7” system; hence the “1-2-4-7” system is more efficient here by two coins … Here the “1-2-4-7” system is further compared with the “1-2-5-10” system, and any other system could be compared in a similar manner. In every case it turns out that the “1-2-4-7” system has an edge over the other systems from the standpoint of number of coins required for a purchase.”