This depends what you are rounding 450 to. If its to the nearest hundred it's 500. If it is to the nearest whole number or tens place then it is 450.
450
450
You do nothing. 450 is already rounded to the nearest ten.
450
As is. It is already rounded to the nearest tens place.
It is already rounded to the nearest ten as 450
450
450
450
450
450
450
450
You do nothing. 450 is already rounded to the nearest ten.
450
450
450 is already rounded to the nearest tens place.