MathNotes: Calculator Notes

What it does

Equations, solved in place Type `2x + 3 = 7` and get `x = 2`. Quadratic and transcendental equations are solved numerically, with every real root listed (`x^2 - 4 = 0` → `x = -2, x = 2`). Multiply or divide with units and the result's unit is derived, not guessed: `100 km / 2 h` → `50 km/h`, `6 kg × 3 m / 2 s²` → `9 N`, `100 N / 2 m²` → `50 Pa`. Derived units (N, Pa, J, W, V) are recognised automatically, and dimensions that don't map to a real physical quantity are quietly dropped.

• 
  I made a web-based notepad with a built in unit calculator2022 · numpad.io · ▲488

  I launched NumPad v1 on here a few years ago, and back then it wasn't much more than a thin CodeMirror wrapper around the calculator engine I'd written. Now I've rewritten it as a PWA that supports multiple documents, persists them to IndexedDB, and has a syncing service for paying customers. Syncing is handled by Automerge[1] under the hood, which should make it relatively easy to get document sharing working too. [1] https://automerge.org/

• 
  CalcMate2023 · accounts.google.com · ▲88

  calculate numbers, dates, units within notes

• 
  Calculator Notepad2022 · chromewebstore.google.com · ▲75

  A free-form calculator for Chrome

• 
  Algebra Calculator2014 · mathpapa.com · ▲79

  What do you want to calculate?

• 
  TCal2022 · apps.apple.com · ▲58

  Notepad calculator app

• 
  Binary Decimal2025 · binarydecimal.com · ▲16

  Your private Notion-style workspace - no login, no cloud

• 
  WallHop – 12ft.io is gone, so I built a replacement▲287

  wallhop is a free paywall bypass. Paste any article link to read it without paywall popups, ads or clutter. No signup, no extension. A simple 12ft.io alternative.

  Growth · 12d ago · wallhop.io

• 
  Prefer▲201

  The execution layer for AEO

  Growth · 24d ago · tryprefer.com

• 
  MakerMap▲197

  A living map of makers and what they’re building

  Growth · 27d ago · makermap.lol

• 
  An e-ink frame that hears birds and draws them as 1800s illustrations▲2,389

  E-ink bird frame for Raspberry Pi - real-time bird detection by audio, fully local AI, rendered as real, hand-cut 1800s bird illustrations. - arnegiacomo/fugleramme

  AI · Sep 2026 · github.com

• WI
  What if the speed of light was 5 km/h?▲629

  Special relativity simulator in which light crawls along at a human speed, so Lorentz contraction, aberration and Doppler shift happen at walking pace.

  Life & fun · Sep 2026 · rivendell.dmitrybrant.com

• 
  Jev▲544

  Fast, structured AI decisions for software automation

  AI · Sep 2026 · console.typesafe.ai

• 
  ReSO AI▲510

  Get discovered & recommended when customers ask AI

  AI · Sep 2026 · resollm.ai

• 
  Kilo Code for iOS and Android▲498

  Start coding agents, control sessions, review PRs. Anywhere.

  Dev tools · Sep 2026 · kilo.ai

• 
  AINA▲497

  Find your job search blind spots with an AI coach

  AI · Sep 2026 · aina-tech.io