The document discusses various numeric systems used in computers including: 1) Binary conversion which involves dividing a decimal number by 2 to get the binary representation. 2) Hexadecimal conversion which involves dividing a decimal number by 16. 3) Logic gates like AND, OR, and NOT that computers use to perform calculations. 4) How negative numbers are represented using 2's complement by "hijacking" the most significant bit. 5) How subtraction is performed by adding the normal representation to the 2's complement.