Because the switching elements in the circuit have two completely different states: on and off, if there is only one switching element, it can be in the on or off state stably. If ON is represented by 1 and OFF is represented by 0, then only 0 or 1 can be represented, which is called bit. Elements such as 16 are arranged together and can be expressed as 000000000000 to1111111.

Decimal is not used because no component with 10 stable state can be found.

The correspondence between decimal and binary is as follows.

Decimal binary

0 0

1 1

2 10

3 1 1

4 100

5 10 1

6 1 10

7 1 1 1

8 1000

9 100 1

10 10 10

1 1 10 1 1

12 1 100

13 1 10 1

14 1 1 10

15 1 1 1 1

Decimal is a decimal one and binary is a binary one.