Fence Paling / Ladder Rung Calculator

m.m.   Span to be filled (millimetres)

m.m.   Paling width (millimetres)

m.m.   Desired gap between palings (millimetres)

If palings cannot be evenly spaced using these exact dimensions, would you
prefer to stretch the gap a little, or squeeze them up (and possibly use an extra paling)?
Stretch the gap
Squeeze them up

                          Start again from scratch