So rather than try to write a description about the numbers I decide to draw up a chart.
Please feel free to download this chart for your own use, and if you do wish to share it, please credit me. Thanks
How to use the Chart
The chart is pretty simple to understand, along the top are 3 columns, starting with Full Stop, 1/2 Stop then 1/3 Stop, reading down each column you see the camera F Numbers. The gap between the F Numbers is the amount of light you are reducing or increasing into the camera.
Lets say you want to reduce the light by 1 Full Stop of light, simply look at the first column titled Full Stops and switching the F-Number on your camera between these settings will decrease or increase the amount of light accordingly. Using the second column and switching between these F-Numbers will reduce light by 1/2 Stop and finally switching between the F-Numbers in the 3rd column will reduce light by 1/3 Stop.
I hope this all makes sense, any questions just let me know in the comments.