There are 90 two-digit whole numbers between 1 and 100.
-21
18
6500 to 7499 -- 1000 numbers
When rounding off, the rule is, "If the first figure to be discarded is 5 or more then the previous figure is increased by 1. Following this rule then 650 is the result of rounding off numbers in the range 645 to 654. As 650 itself is not rounded off then there are 9 whole numbers that can be rounded to 650.
Nine of them.
99 of them.
3 and these are 600,650,and 700
The numbers from 75 to 84 are rounded off to 80 to the nearest ten
There are only 999 three digit whole numbers.
450 whole numbers.
There are 900 three-digit whole numbers between 1 and 1000
7 two-digit numbers.
Ten of them.
90000
90
Infinitely many numbers.1 million and 1 whole numbers . Although, technically 34 million, itself, would not be rounded. This would comprise the numbers from [33,500,000, 34,500,000]. 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.