### A good answer might be:

No. It is a meaningless representation because the digit 8 can not be used with base seven.

# Secret Numbers

The symbols chosen for digits need not be the usual symbols. Here is a system for base four:

    zero  == @     one == !     two == #      three == $

Here is a number written in that system: `!$@#`

       !$@# == !×(!@)$ + $×(!@)# + @×(!@)! + #×(!@)@

The base in this system is written `!@` which uses the digits of the system to mean one times the first power of the base plus zero times the zeroth power of the base.

This example illustrates that positional notation can be used without the usual digits 0, 1, 2, ..., 9. If the base is B, then B digit-like symbols are needed.

### QUESTION 11:

(Frequent Midterm Question: ) What is the base ten representation of the number?