In 12 turns, she lands in a blue space 3 times.
12/3 =4
In 100 turns, it is expected that Myra would land on a blue space '100/4' times
100/4= 25
Which sums up to 25 turns
-1/9+-5/9=
When you are adding a negative number, the operation turns into subtraction:
-1/9-5/9=

Really, it's just subtraction. The simplest form is -2/3, which is equal to -0.66667.
I hope this helps :)
Awww man the other person answered before me :(