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Number Bases Overview

Aug 15, 2025

Overview

This lecture covers the basics of binary and other number bases, explaining how they work and how to convert between different bases.

What Are Number Bases?

  • A number base or numeral system defines how numbers are represented using a set of symbols (digits).
  • Base 10 (decimal) is the standard system, using digits 0–9.
  • Binary (base 2) uses only two digits: 0 and 1.
  • Other common bases include octal (base 8) and hexadecimal (base 16).

Binary System

  • Each binary digit is called a bit and represents a power of 2.
  • Numbers are written using only 0s and 1s; for example, 1011₂ equals 11 in decimal.
  • To convert binary-to-decimal, multiply each bit by its place value (2ⁿ) and add them.

Converting Between Bases

  • To convert from another base to decimal, multiply each digit by its base power and sum the results.
  • To convert from decimal to another base, repeatedly divide by the base and record the remainders.

Other Bases

  • Octal uses digits 0–7, with each place representing a power of 8.
  • Hexadecimal uses digits 0–9 and letters A–F, representing values 0–15, with each place a power of 16.

Key Terms & Definitions

  • Binary — Number system with base 2, using digits 0 and 1.
  • Decimal — Standard number system with base 10, digits 0–9.
  • Octal — Number system with base 8, digits 0–7.
  • Hexadecimal — Number system with base 16, digits 0–9 and A–F.
  • Bit — A single binary digit (0 or 1).
  • Place Value — The value of a digit based on its position and the base.

Action Items / Next Steps

  • Practice converting numbers between binary, decimal, octal, and hexadecimal systems.
  • Review homework or assigned readings on number base conversions.