Price comparison device

A calculating and comparison device comprising:

• (a) a flat planar member with first and second confronting peripheral edges;
• (b) first scale means disposed on one side of said flat planar member, said first scale means comprising a first set of demarcations disposed on said flat planar member and a first set of numerical indicia correlated to said first set of demarcations, said first scale means being positioned so that said first set of demarcations corresponding to said first scale means abuts said first peripheral edge of said planar member;
• (c) second scale means disposed on said planar member, said second scale means comprising a second set of demarcations disposed on said planar member and a second set of numerical indicia correlated to said second set of demarcations, said second set of demarcations being positioned at points removed from said first set of demarcations;
• (d) stretchable alignment means configured and dimensioned to grippingly engage one of a plurality of points on said first peripheral edge and one of a plurality of points on said second peripheral edge, for indicating a first point on said first scale means and simultaneously indicating a second point on said second scale means said stretchable alignment means being capable of stretching to a length required when said alignment means is grippingly engaging said first and second peripheral edges and is oriented at an angle of sixty degrees, and the length of said stretchable alignment means being much greater than its width;
• (e) third scale means disposed on said planar member, comprising a third set of demarcations and a third set of numerical indicia correlated to said third set of demarcations, said third scale means being positioned, configured and dimensioned to have a particular point on said third scale means indicated by said alignment means simultaneously with the indication of said first and second points on said first scale means and said second scale means, the numerical indicia associated with the particular point indicated on said third scale means being selected so that the numerical value associated with the numerical indicia associated with said particular point is a function of a desired mathematical relationship and the numerical values associated with the numerical indicia simultaneously indicated on said first scale means and said second scale means by said alignment means, said third scale means being positioned so that said third set of demarcations corresponding to said third scale means abuts said second peripheral edge of said planar member, said second scale means being positioned between said first scale means and said third scale means.