# Arithmetic Course/Number System

## Number of Base Ten

The number system in use of the ordinary real life is number in of base ten consists of digit from 0 to 9 . Any number greater than 9 can be expressed as

${\displaystyle Ax10^{n}+Bx10^{(}n-1)+...+Zx10^{1}+10^{0}}$

For example

${\displaystyle 121=1x10^{2}+2x10^{1}+1x10^{0}=100+20+1}$

## Number of Base Two

The number system in use of the ordinary real life is number in of base ten consists of digit from 0 to 1 . Any number greater than 1 can be expressed as

${\displaystyle Ax2^{n}+Bx2^{(}n-1)+...+Zx2^{1}+2^{0}}$

For example

${\displaystyle 111=1x2^{2}+2x2^{1}+1x2^{0}=4+2+1=7}$