The chance of matching the full number is of course 1/100. The chance of matching just one of the 2 digits (the first or the second) is 1/10 x 2=1/5 (there are 2 chance of 1/10 as the are 2 digits). When you place a bet on the Lucky Number (an integer between 00 and 99), with a single bet you have 3 different ways of winning and as total winning and as total winning odds the sum of the 3 possibilities: 21/100 (1/10+1/10+1/100).
In simple words when you place a unique bet on a single number you have 21 chance on 100 to win something.
It seems you have calculated the probabilities wrong.
The chance of matching only 1 digit should be 9/100 but not 1/10, as you should excluded the case of matching both digits.