Mathematics Patents (Class 434/188)
- Chalkboard or equivalent means having readily erasable surface (Class 434/192)
- Manually manipulated numeral shaped elements (Class 434/193)
- Numeric value represented by weight placed on balance (Class 434/194)
- Manually manipulated elements having size proportional to numeric value (Class 434/195)
- Indicia-bearing belt or reel-mounted strip (Class 434/197)
- Plaque (e.g., disk, etc.) turnable relative to index (e.g., window in card, etc.) to selectively align different points on plaque therewith (Class 434/198)
- Plaque slidable relative to index (e.g., window in card, etc.) to selectively align different points on plaque therewith (Class 434/199)
- Manually manipulated pin or peg (Class 434/200)
- Electric component included in teaching means (Class 434/201)
- Keyboard or like manually manipulated array (e.g., slides, levers, etc.) (Class 434/202)
- Apertured elements threaded on elongate means (e.g., abacus, etc.) (Class 434/203)
- Means having number of marks (e.g., dots, etc.) or associated physical units (e.g., sticks, indentations, etc.) corresponding to numeric value (Class 434/205)
- Rotatable wheel-shaped element (e.g., ring, disc, cylinder, etc.) having indicia on perimeter thereof (Class 434/206)
- Color used in teaching means (Class 434/207)
- Ball, block, or disk (Class 434/208)
- Division or multiplication (Class 434/209)
- Place value relative to decimal point (Class 434/210)