# Number Systems

Number Systems have been utilized since the ancient times. We have used sticks, stones, bones and seeds to count objects. This has led to the invention of the Abacus, a famous counting machine, still used until now in certain areas or parts of the world. It is a means of expressing or depicting numbers by means of symbols or characters.

In computing or information technology, number systems is a key part in computation and in report or output generation. There are four (4) number systems are used in computer engineering, computer science, and in information technology. These number systems are binary, octal, decimal and hexadecimal.

Binary is a base-2 number system that uses only two numbers in its system, namely only zero (0) and one (1). Bi is a prefix which means two. To differentiate or identify this number system from other number systems, we use the number 2 as a radix on any given binary number. In digital circuits and electrical machines, this has also relates to the concept of the OFF and ON state. OFF equals to zero (0) and ON equals to one (1).

ex. **101 _{2}**

**1011 _{2}**

Conversion of Binary to Decimal

There are different methods used in converting binary to decimal. One of which is using the exponents and powers of 2 and adding which portion has the bit placement of 1.