If you roll two fair six-sided dice, what is the probability that the sum is 9 or higher?  

There are 36 different combos for the two: 6 possibilities for the first die times 6 for the second. 

Out of those 36, 10 have a sum of 9 or higher: 
3&6, 4&6, 4&5, 5&4, 5&5, 5&6, 6&3, 6&4, 6&5, 6&6

The probability is 10/36, which reduced is 5/18. 
As a decimal it is 0.2 and as a percent it is 27.%. 
Hope this helps!