math
posted by lindy .
how many 2 digit numbers can be written so that the second digit is greater than the digit before it ?

12 through 19 = 8.
23 through 29 = 7.
34 through 39 = 6.
45 through 49 = 5.
56 through 59 = 4.
67 through 69 = 3.
78 through 79 = 2.
89 = 1.
Total = 36 Numbers.