Move blue T-bar to enter positive number x
Move yellow slider to enter positive number y
Orange T-bar shows z = xy
At point C there are 3 pink sliders (sliding in slots of violet, orange and blue bars respectively) connected together by revolution joints. The screw lead must be large enough to avoid self-locking.
The video shows operation 4050 = 2000 and then 50*80 = 4000.
The mechanism works on similar triangles rule. From triangles OBC and OAD: OB/OD = BC/AD
OB = x ; AD = y ; BC = z ; OD = k = 100 mm (constant) then z = (xy)/k
For the X and Y scale, 1 mm corresponds 1 unit.
For the Z scale, 1 mm corresponds 100 units.
The division x = z/y can be performed on this mechanism: enter z and y and get x.