Answer:
1. 1/2, rise/run and since you rise one and run 2 it'll be 1/2
2. 7/0 = undefined automatically, there is no value(undefined) if there is no run
3. rise: 28 - 18 10 5
_______ = _____ = _____ = 5
run: 4 - 2 2 1
4. 1, it rises 1 and runs 1