Use of …aine added to numbers to signify ‘about’

Question

In your lesson, you describe …aine as being ‘about’ or ‘or so’ and yet in the example you translate deux douzaine… as being ‘two dozen’. In UK English , a dozen is NORMALLY, exactly 12, but I acknowledge it CAN also have ‘or so’ connotations.  Perhaps not the best example?  Love the site for learning French by the way. Much better than well-known alternatives)

Accepted Answer

Michael, the lesson does cover this. 
The approximation expression in French equivalent to ‘ a dozen or so’ in English is ‘ une dizaine de…’. 
‘Une douzaine de… ‘ is an exception to the use of ‘-aine’ indicating approximations. It is not an approximation at all, but an exact quantity - ‘ 12 ‘, one dozen, not more or less. 
From the lesson
    As in English, douzaine (dozen) means 12 rather than being an approximate number, but the construction is the same as for approximate numbers
https://progress.lawlessfrench.com/revision/grammar/how-to-make-approximate-numbers-such-as-une-dizaine-ten-or-so

Answer

Although the lesson does cover douzaine being an exact number, it’s a bit confusing to include it in the table under the heading "Approximate".