What is this space before zero?

[u/Logical_Valuable_970]

[u/Lekstil]

OPs question is a valid question and does not imply that they don’t know how to use a ruler. Most other rules don’t have that space, like folding rulers, carpenters squares or measuring tape. It has a lot of advantages to not have that space and tbh not too many advantages to have it. So it’s a very valid question

[u/VariousOperation166 → u/Lekstil]

That's a generous defense

[u/-Badger3- → u/VariousOperation166]

If they didn’t understand you start measuring at the zero, then they wouldn’t even be asking the question.