0984
Number Systems
Data Representation · 4 question types
Exam Frequency Analysis
Past paper frequency (2018 to 2024)
This topic accounts for approximately 12% of your exam marks.
stable
High
Stable12%
Binary/hex conversion and binary arithmetic appear in every Paper 1. Consistently 8 to 15 marks.
There are two methods for each direction. Method 1 goes through binary as a stepping stone and is foolproof; method 2 uses arithmetic directly and is faster once you are confident.
Denary to hex, Method 1: via binary
- Convert the denary number to an 8-bit value.
- Split the binary value into two (groups of 4 bits).
- Convert each nibble to its denary value (0 to 15).
- Write each value as a hex digit using the A to F table for 10 to 15.
Denary to hex, Method 2: divide by 16
- Divide the number by 16. The whole part is the first hex digit; the remainder is the second hex digit.
- Convert any value 10 to 15 to its hex letter (A to F).
Hex to denary, Method 1: via binary
- Convert each hex digit to a 4-bit binary nibble.
- Join the two nibbles into an 8-bit binary number.
- Convert the binary number to denary using place values.
Hex to denary, Method 2: multiply by 16
- Multiply the first hex digit by 16.
- Add the second hex digit to the result.