Decimal numbers


When we count normally we are using a type of counting called decimal. This means we use 10 figures in our counting before we need a second column.
abacus.jpg
0
1
2
3
4
5
6
7
8
9

and then we need a second column for

10

Binary numbers


Computers count in a different way. This is because they are made up of electrical circuits which can be on or off. This means that computers only use the characters 0 (or off) and 1 (or on). This is called the binary counting system.

See if you can write the numbers 0 to 9 in Binary. Check here to see if you were correct

Hexadecimal numbers


Computers also sometime use hexadecimal numbers for counting. This means that they use 16 characters for counting before you need a second column. 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F and only then 10. This is often used for colours in web pages.

Assignment


In excel we can convert these sorts of numbers from one to the other using the dec2bin and dec2hex functions.

You should create a dec bin hex converter in excel to convert all numbers from 0 to 255 in decimal to their binary and hexadecimal equivalents.