The Lorentz Transformation tA = [tB+vxB/c^2]/sqrt(1-v^2/c^2) can be simplified to tA = tB (1-v)/sqrt(1-v^2), if we adopt these conventions: 1) Refer to v as a fraction of c. Thus every time we write v/c in the original formula, we write v, in the understanding that these v units are units of c. 2) Refer to length in light-seconds = x/c. Thus every time that the original formula writes x/c, we write x, in the understanding that these x units mean x light-seconds. This way, in the numerator, the sync factor vx/c^2 can be broken down into (x/c)(v/c). Expressed with this convention, x/c becomes x light-seconds and v/c becomes v = the corresponding fraction of c. In the denominator, the expression sqrt(1-v^2/c^2) becomes sqrt (1-v^2). Thus the LT looks as follows: tA = (tB + xB*v )/ sqrt(1-v^2) 3) But it seems as if xB could also be replaced by tB. If a point is deemed to be xB light-seconds away from the origin of the coordinate system B, it is because it is assumed that light takes tB seconds to reach that place as measured in B frame. In fact, if xB in our notation is (x) km / (c) km/s and c is the unity, the expression is equivalent to tB. Thus the LT adopts this look: tA = (tB + tB*v )/ sqrt(1-v^2) = tB (1+v)/ sqrt(1-v^2) Although I cannot do the intermediary algebra, it appears that these other expressions give the same result: tA = tB * sqrt [(1+v)/(1-v)] tA = tB * sqrt(1-v^2) /(1-v) I cannot think of any practical situation where x in km is needed. Is this right or have I missed anything?