File:Abacus-Whole-Numbers.png|Using an abacus to count whole numbers up to 1,000,000. The abacus shows the number as a sum of the units: ones, tens, hundreds, etc. | File:Abacus-Whole-Numbers.png|Using an abacus to count whole numbers up to 1,000,000. The abacus shows the number as a sum of the units: ones, tens, hundreds, etc. |