Since all numerical systems share with one another that they count, at least theoretically, physical units, or fractions thereof, they are interchangeable, can be compared along the same standards, can be converted into one another, etc.
| [decimal digits] | [binary digits] |
|---|---|
| 0000 | 0000 |
| 0001 | 0001 |
| 0002 | 0010 |
| 0003 | 0011 |
| 0004 | 0100 |
| 0005 | 0101 |
| 0006 | 0110 |
| 0007 | 0111 |
| 0008 | 1000 |
| 0009 | 1001 |