GCSE EDEXCEL Topic 2A Number bases In this video we provide an introduction to the three different base number systems you need to know about, these include: Decimal (base-10), Binary (base-2) and Hexadecimal (base-16). Also in this topic... GCSE EDEXCEL Topic 2A Bit patterns GCSE EDEXCEL Topic 2A Signed integers using two’s complement GCSE EDEXCEL Topic 2A Adding two 8 bit binary integers GCSE EDEXCEL Topic 2A Binary shifts GCSE EDEXCEL Topic 2A Why hexadecimal is used in computer science