Let me first re-phrase your question: What is the number of (positive) integers less than 10000 (5 digits) and greater than 999 (3 digits)?
The greatest 4 digit integer would be 9999.
The greatest 3 digit integer would be 999.
Let's do some subtraction: 9999 - 999 = 9000
This works because as we count up from 999, each positive integer encountered satisfies your requirements until reaching 10000.
The lowest positive 4-digit number is 1000
-22
There are one thousand. Starting at 2000 and going to 2999
-48
5*5*4*4 = 400
4
22 of them.
The smallest, positive 4-digit multiple of 17 is 1,003.
The lowest positive 4-digit number is 1000
There are 294 such numbers.
from 1000 to 9999, ie 9999 - 999 = 9000
The lowest 4 digit number is -9999. The lowest 4 digit POSITIVE number is 1000.
18 positive integers and 36 integers (negative and positive)
4,000 even numbers, 4,000 odd numbers.
possibly than 20, 3040 3041 etc 3050 3051 etc
To find the least positive 4-digit multiple of 7, we need to divide 1000 by 7 to get the closest whole number, which is 142.857. We then multiply this whole number by 7 to get 994, which is the largest 3-digit multiple of 7. Therefore, the least positive 4-digit multiple of 7 is 1001.
-22