# An eight-sided dice

**Discrete Mathematics**Level 5

An eight-sided dice is rolled 3 times.

If the number obtained on the third roll is equal to the sum of the numbers obtained on the first roll and second roll, what is the probability that **at least one** of the rolls was a 2?

If the probability can be expressed as \(\dfrac ab\), where \(a\) and \(b\) are coprime positive integers, find \(a+b\).