Do you know why numbers look like they do? Someone, at some point in time, had to create their shapes and meaning.
Watch this short presentation and then you will know how our Arabic numbers were originally created a very long time ago and what logic the people that created them used to determine their shapes. It is really very simple and quite creative? You have to admire the intelligence of a person that created something so simple and perfect that it has lasted for thousands and thousands of years and will probably never change?
When the presentation gets to the number "seven" you will notice that the 7 has a line through the middle of it. That was the way the Arabic 7 was originally written, and in Europe and certain other areas they still write the 7 that way. Also, in the military, they commonly write it that way. The nine has a kind of curly tail on it that has been reduced, for the most part nowadays, to a simple curve, but the logic involved still applies.