How to determine how many bases a number is?

Give a point a number and determine what base it is??

1, binary: only 0 and 1 in it

2, octal: each single number is between 0-7 (inclusive). Such as 175,023,312, etc.

3, hexadecimal
Its rule is "every hexadecimal one".

The base of hexadecimal number is 16,

The numbers used are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F.

A-F represent decimal numbers 10-15 respectively.
The technical rule of hexadecimal numbers is "every hexadecimal one", and the weight of each bit is identified by the N power of 16.
The representation of hexadecimal numbers starts with 0x.
Example: 0xAF=175
Usually, for the representation of hexadecimal numbers, 16 or H can be marked in the lower right corner of the number, but in C language, the number 0 and the letter X are added in front of the number.0X to indicate.For example, 12AF is represented as 0X12AF in C language.

4. Decimal: each single number is between 0-9 (inclusive).