Tactile Instruments & Classroom Manipulatives
Dedicated handheld Reverse Polish Notation calculators, precision physical math manipulatives, modular desk stands, and 100% free open-source CAD/STL downloads. Engineered for focus, tactile feedback, and concrete mathematical mastery.
Equipping a Math Lab, Department, or School Co-op?
We accept standard school purchase orders (Net-30 payment terms), provide signed W-9s, and offer volume tiered classroom discounts. Includes our Perpetual Reproduction License—print unlimited student lab workbooks forever with zero recurring software fees.
SC-32 Scientific RPN Calculator
Fraction Studio Proportional Towers
Single-color precision proportional blocks with debossed 4-face notation (fraction, decimal, percent, degree). Halves, quarters, and eighths physically align flush on any classroom table with zero loose trays required. Housed in a modular 3x2x13U Snapfinity Gridfinity enclosure with bi-directional sliding hard lid. (Optional snap-on TPU non-skid feet sold separately.)
Sectional Classroom Planetary Clock
Internal 12:1 planetary gear core with synchronized hour and minute hands. Removable 15-minute quadrant wedges fit standard 2x1x13U Snapfinity Gridfinity workstation box and desk stand for kinesthetic elapsed-time discovery. (Optional snap-on TPU feet sold separately.)
Algebra Factoring Studio & Tiles
Chamfered polynomial tiles for \(x^2\), \(x\), and \(1\) paired with slotted stage factoring rails. Housed in a 3x1x13U Snapfinity Gridfinity box for binomial multiplication, trinomial factoring, and completing the square. (Optional snap-on TPU feet sold separately.)
Ten-Frame Dual Stage & Carry Shelf
Dual 2x5 counting stage with an elevated carry shelf, 20 square miniblock counters (19×19mm), and a 2U cube "10" carry block. Housed in a 3x1x13U Snapfinity Gridfinity enclosure with integrated carry shelf for base-ten regrouping and make-a-ten mental arithmetic. (Optional snap-on TPU feet sold separately.)
Math Domino Studio & 12-Frame Set
30 miniblock domino tiles (28 double-six + 2 blanks) with direct 1064nm IR laser-foamed pips, a 12-frame regrouping tray (10+2 divider), and a stackable doubling snap lid in a 3x1x13U Snapfinity Gridfinity box. (Optional snap-on TPU feet sold separately.)
Probability Dice & Spinner Pack
Ultra-low-friction centered spinner with interchangeable 4, 6, 8, and 12-sector discs and mass-compensated polyhedral dice pack. Housed in a 1x1x13U Snapfinity Gridfinity box for empirical probability experiments. (Optional snap-on TPU feet sold separately.)
Unit Circle Trigonometry Volvelle
Flat dual-disc rotating dial with laser-engraved degree angles, radian measures, and exact \((\cos \theta, \sin \theta)\) coordinate pairs. Flush center brass eyelet for binder storage.
Counting Tiles & Planar Array Studio
144 precision stacking tiles (4 colors × 36) in a 3x1x13U Snapfinity Gridfinity box with 12-miniblock array docking lid. Bridges one-to-one counting, the 12×12 multiplication matrix, partial-product area models, and the Four-Color Map Theorem. (Optional snap-on TPU feet sold separately.)
Prime Factor Studio & Factor Towers
29 proportional logarithmic prime factor blocks with a 3x1x13U Snapfinity Gridfinity box featuring prime power storage lid sockets. Stacking prime blocks physically multiplies them, proving the Fundamental Theorem of Arithmetic. (Optional snap-on TPU feet sold separately.)
SC-32 Scientific RPN Maker Kit
The definitive dedicated physical RPN calculator. Raspberry Pi RP2350 silicon, 43 snap-dome tactile switches (400g actuation), transflective graphic LCD, and tool-free sliding dovetail chassis with 8 interchangeable faceplate finishes. 100% pre-soldered, 5-minute snap assembly. SAT/ACT/AP approved.
SC-6 Elementary Edition
Tactile arithmetic calculator designed for primary and intermediate students. Clean White PLA 2.0+ lab chassis, Slate Gray tool-free sliding cowl, 400g snap-dome keys, and default 4-line XYZT operational stack (with toggleable 2-stack mode for counting racks and dice) using crisp right-aligned Terminus font.
StackCalc Digital Twin App
The 1:1 software twin of the SC-32 physical calculator. Runs the exact same core arithmetic engine with haptic feedback, customizable skins, and wrist calculation on Apple Watch.
Modular 3-in-1 Puzzle Stand
Zero-waste packaging insert that reconfigures into a 78° shelf display with TPU pouch dock or a 10° ergonomic desk wedge. 100% recyclable interlocking design with laser-cut living hinges.
Flexible TPU Travel Pouch
Drop-tested shock-absorbing pouch in azure blue with debossed logo, integrated 3-ring binder clip, and lanyard attachment. Fits SC-32 and SC-6 snugly with impact-dissipating perimeter ridges.
Lifetime Replacement Parts Service
Never retire a classroom set again because a tile rolled under a radiator. Order individual replacement fraction blocks, algebra tiles, counters, or stand legs 3D printed from the exact Git commit of your set. Structured at 50% over amortized cost to eliminate kit arbitrage.
Manipulative Investigation Decks & Lab Guides
60-card tactile problem decks and spiral-bound student laboratory workbooks. Each card walks students through the Concrete-Representational-Abstract (CRA) continuum: first testing quantities with physical blocks, then sketching diagrams, and finally recording equations.
Included in Every Curriculum Pack:
- ✓ 60 double-sided wipe-clean challenge cards
- ✓ Teacher rubric with step-by-step pictorial solutions
- ✓ Reproducible student lab worksheet templates
- ✓ Aligned with Common Core & State Math Standards
Self-Manufacture With Your 3D Printer
Every physical manipulative, calculator enclosure, and desk stand in the StackCalc ecosystem is open hardware. Download print-tested STLs and 3MFs calibrated on Prusa research printers with PrusaSlicer, or download directly from Printables.
WARNING: CHOKING HAZARD – Small parts. Not for children under 3 years. Counting tiles, dice, and fractional blocks are designed for classroom instruction (ages 5+) under adult supervision.
Produced exclusively from odorless, renewable, food-contact grade PLA and impact-absorbing PETG. Zero BPA, lead, PVC, or phthalates. Completely washable and sanitizable between class periods.
Classrooms lose pieces. If any tile, token, hand, or block ever goes missing or gets damaged, order individual replacement components anytime starting at $2.49 with guaranteed 100% CAD fit by matching the Part ID on your kit's included Archival Reference Card.
The SC-32 Scientific Calculator is fully permitted on SAT, ACT, PSAT, AP Calculus, and AP Physics exams. Non-CAS calculation core with zero wireless radios or cheat vulnerabilities.
K–12 School District Purchase Orders & Bulk Procurement
Direct vendor onboarding, Net-30 invoice terms, and federal Title I / STEM grant compliance.
✓ DISTRICT POS & NET-30 TERMS
We accept official school district and university purchase orders. Email your PO to quotes@stackcalc.io for immediate Net-30 order fulfillment and automated electronic invoicing. W-9 forms provided upon request.
✓ FEDERAL & STATE STANDARDS ALIGNMENT
Aligned to Common Core (CCSS.MATH.CONTENT.3.NF.A.1, HSA.SSE.A.2, K.OA.A.4) and Texas Essential Knowledge & Skills (TEKS). Fully eligible under Title I (Academic Achievement) and Title IV STEM initiatives meeting ESSA Tier 4 evidence standards.
✓ ZERO-PREP & 60-SECOND INVENTORY
Each kit includes 5 laminated, 5-minute table-group student activity cards for instant deployment. 42mm Gridfinity nesting allows teachers to visually verify that 100% of blocks and tiles are accounted for in under 3 seconds before class dismisses.
| DIMENSION | LEGACY IN-FIX CALCULATORS | COMMODITY SCHOOL PLASTICS | TRADITIONAL SENSORY SETS | STACKCALC ECOSYSTEM |
|---|---|---|---|---|
| Logic System | In-fix parentheses soup, hidden order of operations, syntax errors | None (disconnected toys without computational link) | None (rote sensorial isolation) | Pure RPN: Zero parentheses. 1:1 concrete block to hardware stack parity. |
| Durability / CMF | Flimsy injection plastic, mushy membrane keys, battery acid leaks | Thin brittle polystyrene, pastel colors that chip | Softwood, chips easily, moisture expansion | High-rigidity technical polymers (PETG/PLA 2.0+), 400g metal snap-dome keys. |
| Modularity & Storage | Monolithic brick; zero desk organization | Loose unorganized plastic tubs; pieces scatter across carpet | Bulky wooden trays requiring dedicated storage shelves | 100% Gridfinity compatible standard. Lid doubles as a desk workbench. |
| Software Subscriptions | Paid emulator licenses ($15/seat/year recurring school fees) | Fragile companion iPad apps with ads and notifications | None | Zero subscriptions. Perpetual classroom reproduction license included. |
| Repairability | Proprietary, non-repairable, landfill bound | Discard and re-purchase entire kit when parts vanish | Costly hand-carved replacement pieces with long lead times | 100% Open Source. Free downloadable 3MFs to 3D print spares for pennies. |
StackCalc connects tactile physical manipulatives, dedicated hardware calculators, and modern software into a single unified learning path. Each manipulative stands on its own for classroom instruction, while seamlessly preparing students for advanced calculation and STEM problem-solving.