90 rounded to the nearest 1, or whole number is 90. This is because 90 is already a current whole number. We know this because there is no decimal point following it.
90
It is 90 when rounded to the nearest ten
90
8.6
It is then 90 when rounded to the nearest ten
It is already is rounded to the nearest ten. The answer is 90.
90
90
90
90
90
90