Question 848090
The word "about" doesn't mean exactly. 
There is only one exact measurement and there is mathematical exactness and practical exactness. 
3 and 2 3/4 are about the same if I use a ruler that only has 1 inch increments. 
They are not as close as 3.9999 and 4.0001 are to each other but that's all a matter of how precise your definition of "about" is.