Must the approximately equal sign be used for rounding? In junior high school about equal sign can be used for into one, give up

Must the approximately equal sign be used for rounding? In junior high school about equal sign can be used for into one, give up

It can be rounded. This one is often used. It can also be used as the method of entering one, that is, whether the following is greater than five or not. Of course, there is the method of rounding off, even if it is greater than five