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.
There are 90 such numbers.
There are 90 two-digit numbers... starting with 10 and ending with 99.
90
90
90
There are 90 such numbers.
There are 90 two-digit numbers... starting with 10 and ending with 99.
90
90
90
90
90
9
90
there are no 3 digit tis two digit! :) * * * * * 90 of them.
90 of them.
80