100
Half of them. Every other number from 0 to 99998 is even. Since there are 90,000 five digit numbers, that means that 45,000 of them are even.
There are 450 even three-digit integers, from 100 to 998. This excludes numbers with leading zeroes (000 to 099).
There are 4500 such numbers.
500 or so.
With a total of 90,000 five digit numbers, we can conclude that there is 45,000 EVEN five digit numbers.
878 three digit numbers have an even number of factors. Every factor of a number has a pair, so there ought to be an even number of factors for every number. However, if a pair of the factors are the same number, then there will be an odd number of factors, that is if the number is a perfect square. Assuming three digit numbers are 100 to 999: From 100 to 999, the perfect squares are 102 = 100 to 312 = 961, a total of 31-10+1 = 22 numbers. So of the 999-100+1 = 900 three digit numbers, 22 have an odd number of factors, so 900-22 = 878 have an even number of factors.
All of them.
4,000 even numbers, 4,000 odd numbers.
100
There are 450 even three-digit integers, from 100 to 998. This excludes numbers with leading zeroes (000 to 099).
2240
There are many 4 digit numbers having 3 and 11 as factors. One of them is 1089 whose factors are 3,3,11,11.
Half of them. Every other number from 0 to 99998 is even. Since there are 90,000 five digit numbers, that means that 45,000 of them are even.
There are 450 even three-digit integers, from 100 to 998. This excludes numbers with leading zeroes (000 to 099).
There are 449999 such numbers.
500 or so.