well, my idea is plot a line on XOY plane. let the number line as x-axis, make y-axis, we just need a line that cross (1/6,0) for example y = x/6 - 1/6, next we need two simple pair number (x,y) on the line as base to draw the line we can choose (1,0) and (7,1). x-intersect that line is desired 1/6 position on the number line
