In the video below Simon applies his knowledge of combinatorics to calculate the total number of possible colours one can create in CSS. I didn’t ask him to do this. In fact, I had no idea what he was doing when I started filming. I saw him studying the colour combinations on this webpage the http://www.w3schools.com/colors/colors_hexadecimal.asp where colour values are explained:

RR (red), GG (green) and BB (blue) are hexadecimal integers between 00 and FF specifying the intensity of the color. For example, #0000FF means the purest shade of blue, because the blue component is set to its highest value (FF) and the others are set to 00.

In each colour, Simon counted 16 possible first digits and 16 possible second digits. He then came up with the idea that that makes the total number of combinations possible for each colour 16 x 16 or 256. Since there are three primary colours (RGB) with 256 combinations possible in each Simon then calculated the total number of possible combinations of digits within a hexadecimal integer: 16 777 216!

I believe he did a good job. Especially considering he has only recently turned 7 years old.

Later the same evening Simon helped his little sister to create new “purest”colours for her drawing: