I am putting into point slope formula, the rise is 1 and the run is 1/2. how do I write the slope if the run is a fraction?

When you have a fraction in the denominator, you invert it (change 1/2 to 2/1) and multiply:

1 1 2

--- = --- * --- = 2

1/2 1 1

A second way to think of it is that 1 is twice as big as 1/2, so the ratio 1/(1/2) = 2.

A third way to do it is to multiply the numerator and denominator by the reciprocal of the fraction. The reciprocal of 1/2 is 2/1 = 2, and (1/2)*2=1:

1 1 2 2

--- = ------ * --- = --- = 2

1/2 (1/2) 2 1

--- = ------ * --- = --- = 2

1/2 (1/2) 2 1

All three ways are equivalent.