algorithm - Recognition of numbers in images(Matlab)

I am learning image processing and i am trying to start my first project, that is Simple number recognition in an image.

So far i have applied thresholding to the image. Now i would like to know some algorithms by which my system can recognize the number in the image. Preferably the algorithm must be simple and it doesn't have to robust as i am would be generating the image in paint using the same font.

I have looked at the similar questions here on SO and they all point out to using libraries. Remember guys i am trying to learn so please don't point out some libraries.