Everything a computer stores is binary. This unit covers binary and hexadecimal numbers, how integers and characters are encoded, and how logic gates and truth tables turn those bits into decisions.
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Number systems: binary and hexadecimal
Computers store all data in binary (base 2), using bits that are either 0 or 1.
Hexadecimal (base 16) uses the digits 0 to 9 and then A to F, where A is 10 up to F is 15.
Hexadecimal is shorthand for binary: each hex digit maps to exactly four bits (a nibble), so 1101 is D and 0110 is 6.
To read a binary value, add the place values of the bits that are 1. For example 10110 is 16 plus 4 plus 2, which is 22.
Check you've got it
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1. What is the denary (decimal) value of the binary number 10110?
2. What is the hexadecimal equivalent of the 8-bit binary number 11010110?
3. Which logic gate outputs 1 only when its two inputs are different?
4. What range of values can a 4-bit two's complement integer represent?
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