Infinitely many numbers.
101 whole numbers . Although, technically 800, itself, would not be rounded. This would comprise the numbers from [750, 850]. In the first case the 5 is rounded up while in the second it is rounded down. This is consistent with the rule of "Round up or down so that the new last digit is even". This is the default rounding mode used in IEEE 754 computing functions and operators.
All numbers can be rounded to the nearest ten.
There are infinitely many such numbers.
999 of them.
70
0
All numbers can be rounded to the nearest ten.
An infinite number.
88500
530
The numbers 250-259 can be rounded to 300. Also 301-349 can be rounded down to 300. This works if you are rounding by the nearest hundreds place.
1000
There are infinitely many such numbers.
999 of them.
Well, honey, any number that ends in 0 can be rounded to the nearest 500. So, technically, there are infinite numbers that can be rounded by 500. But if you want a specific range, let's say -500 to 500, then that's 2001 numbers. Hope that clears things up for ya!
70
70
33,500,000 to 34,499,999