If you include 100 and 200, then there are 11 of them.
9 show the numbers
9
300
How many times does the digit 1 occur in ten place in the numbers from 1 to 1000?
there are no 3 digit tis two digit! :) * * * * * 90 of them.
There are 90 of them.
There are 900,000,000 of them.
300
How many times does the digit 1 occur in ten place in the numbers from 1 to 1000?
there are no 3 digit tis two digit! :) * * * * * 90 of them.
90 of them.
There are 900,000,000 of them.
There are 90 of them.
There are 5 of them.
There are no pairs of 2-digit numbers with a difference of 90 if both numbers are positive or both negative. However, with one positive and one negative, there are 71 pairs.
This is only possible if one of the digits is equal to zero. There are 90 3-digit numbers with a zero in the 10's place, and 90 3-digit numbers with a zero in the 1's place - and 9 numbers that have both a zero in the 10's place and a zero in the 1's place; these would be counted double if you just add the first two. So, you get: 90 + 90 - 9 such numbers.
There are infinitely many such numbers. For example, 123,456,063
13
3