For example, in the ruler, the bottom row goes from 0 to 31 cm from left to right and the upper row goes from 32 upwards from right to left?
EDIT: Here is the manual for the tablesaw pictured above. There is no mention of that scale, and it the drawings it looks like it should be a cm/inches scale.
EDIT2: I had e-mailed the manufacturer about it (Bosch), and they told me to contact an authorized repair store about the matter!? So even the manufacturer have no idea what it is supposed to be.
Best Answer
You have a "reversible" fence. One set of measurements are for when the fence is on the right side of the blade, and the other set of measurements are for when the fence is on the left side of the blade.
Remove those 2 red knobs on the right side of the fence and remove the bolts/fence. Now put the bolts through the other side (where the red knobs are) and put the fence on and the knobs. Remove the fence assembly from the track, move to the other side of the blade, put fence back onto track, now you can measure/cut from the other side of the blade.