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

$A\times 10^{n}+B\times 10^{(n-1)}+\cdots +Z\times 10^{1}+10^{0}$

For example

$121=1\times 10^{2}+2\times 10^{1}+1\times 10^{0}=100+20+1$

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

$A\times 2^{n}+B\times 2^{(n-1)}+\cdots +Z\times 2^{1}+2^{0}$

For example

$111_{2}=1\times 2^{2}+2\times 2^{1}+1\times 2^{0}=4+2+1=7$