500 of them.
9000 integers.
31.how do you solve?
128!
From 1000 to 9999 (inclusive) there are 9999 - 1000 + 1 = 9000 integers. Half of which are even, half of which are odd. So the answer is 9000/2 = 4,500.
500 of them.
9000 integers.
There are 2828 integers between 1000 and 9999.
There are 30 such integers.
333 integers.
899
31.how do you solve?
128!
90 palindromes.
There are 128 integers between 100 and 1000 that are divisible by seven.
From 1000 to 9999 (inclusive) there are 9999 - 1000 + 1 = 9000 integers. Half of which are even, half of which are odd. So the answer is 9000/2 = 4,500.
There are 10 even integers between -10 and 10 (excluding -10 and 10).