The chance of rolling a number greater than 4 (a 5 and 6) is 2/6 = 1/3 after simplification. The probability it WON'T happen is 1 - 1/3 = 2/3.
The ratio of against to for is 2/3:1/3
You can further simplify this ratio by multiplying each side by 3 and yielding
2:1.
The chance of it not happening is twice as likely as it is to roll a number greater than 4
