1921 Census - brackets around age

I have taken a very quick look at the 1921 census for Oxford and for Parrsboro.  In both cases, the ages for many people are contained within brackets.  At first, I thought that might indicate an "estimated" age... but now realize there are far too many bracketed ages.  Does anyone have a better guess?

Gerry


[Non-text portions of this message have been removed]