A = 0.625
There are 8 points between 1 and 0 so divide 1 by 8.
1 / 8 = 0.125
Each point has a value of 0.125.
You can minus 0.125 from 1 until you reach A.
Or you can multiple 0.125 by the number of points from 0 to A, including A.
1 - 0.125 - 0.125 - 0.125 = 0.625
0.125 * 5 = 0.625
A = 0.625