The conversion process from the decimal number system is another number system is the first process of converting a number system that anyone can do. The process converts number from this number system is other number system to start from converted the decimal number system is binary number system, octal number system and hexadecimal number system. The process of convert decimal is binary number system has two steps. Short division with base number system conversion is to start of the process of convert decimal is binary number system. And the second stage is after dividing short binary system, remove the debris and the results derived sequence from bottom to top. The process of convert decimal is octal number system and the process of convert decimal is hexadecimal number system It have the process of converting binary system is similar to the process of converting decimal to binary system. Is short by dividing the number to convert. Then the results and fragments derived sequence from bottom to top.