A single-digit number can be based on different compound numbers.
The 7, for instance, can be based on 16, 25, 34, 43, 52, 61, 70, 79, 88, and 97. Although they all reduce to 7, each changes the personality of the 7 to some extent. In some cases, the changes are quite dramatic, such as when the double-digit number is a Master number or a Karmic Debt number.
When a single-digit number is based on a double-digit number, it’s a good habit to include it in the numerology chart.
If a 7 is based on 25, write 25/7, if it’s based on 34 write 34/7.
A double-digit number’s characteristics are dominated by that of the single-digit to which it reduces. The double-digit number highlights certain aspects and diminishes others, but it never eliminates any aspect completely.
For example, a 7 based on 25 is not as withdrawn as a 7 based on a 16, while a 7 based on 34 is more creative than other 7s.