estimating and getting wrong (or right) answers?

When I was a mathematics major, some students joked 'for large values of
one, "1+1=3"' and I thought about this recently.  Even at 1:59, it's the
one o'clock hour, and similarly, 19 is in the 10s, and similarly, 1.9 is
in 1.n, so does the joke have some truth?

How would you categorize/classify this?

Do these sorts of things have truth for some definitions but not others?

Is there any mathematics sub-field that uses such ideas?