# CSCI 1111 Lecture Notes - Lecture 2: Operand, Reserved Word, Hexadecimal

## Document Summary

Normally it is believed to be base ten numbers. Each digit must be 0-9 and each digit"s place is weighed by increasing powers of 10. In base 2, each digit must be 0-1 and each digit"s place is weighed by increasing powers of 2. Memory of computers are based on switched (on/off) 0 or 1. Decimal numbers use weighed powers of 10: 212 = 2*102 + 1*101 + 2*100. Binary numbers use weighed powers of 2: 1101 = 1*2^3 + 1*2^2 + 0*2^1 + 1* 2^0 (13) R = 1: biggest number that can be written in binary 1111. Base 10 is not used in computer science, only base 2 or base 16. The range of numbers that can be represented in a set number of bits is limited. 1 bit is 0 or 1; 1 byte is 8 bits. Negative numbers in binary are two"s complement. In computer science, many processes are followed through protocols.