The octal system uses base 8. The only available digits would be 0, 1, 2, 3, 4, 5, 6, and 7. If the value 1358 is converted to an decimal value, what would it look like expanded?

It will result in an error

Explanation:

If the numbers 1358 are the numbers to be converted, there will be an error because in Computer Arithmetic, no number can be higher or equal to its base.

Also, your base range for octal is 0 - 7 hence, 8 is invalid.