Welcome to MathNotes. This help center covers install, core features, math capabilities, settings, and FAQ. Everything matches the app's actual behavior.
Getting Started
- Install MathNotes.
- On first launch you'll see 10 pre-filled life & engineering example notes (family budget, dinner split, trip sharing, motor reduction, resistor divider…). Tweak a number to try, or long-press to delete. The example notes are now multilingual: on first launch they follow your system language (Simplified Chinese, English, Japanese, Korean, French, German, Spanish, Arabic), falling back to English for unsupported languages.
- Tap "+" to create a new note.
- For the full tour: Settings → About → How to use notes.
Inline Calculation in Notes
Type an expression and end the line with =; the answer appears in orange:
rent + coffee × 30 =
Supports arithmetic, parentheses, percentages (20 + 20 × 15% = 23), negatives and decimals. Change an earlier number and the result updates.
Writing is smoother: spaces are added around = automatically (x= becomes x = ), and between a trailing number and a system unit. Non-system words (like xyz) stay plain text.
Variables
Define with name=value on its own line; use it anywhere; edit the definition and the whole note recomputes.
coffee = 4.5 coffee × 5 = rent + coffee × 30 =
Great for defining exchange rate, unit price, or hourly rate once and referencing it everywhere.
Unit-aware variables (distance = 100 km) carry the unit downstream (distance × 2 = shows 200 km). Composite units are derived automatically: mix units with ×/÷ and the result's unit is assembled by dimension — speed as km/h, rotation as rpm/m/min; explicitly written m/s is recognized too. Grayed units: the number is orange, the unit is gray — and units you type are auto-grayed.
Built-in Calculator
- Percent:
100 + 5% = 105 - Sign toggle
- Smart repeat: press
=repeatedly to keep adding (5 + 3 = = =→ 8, 11, 14); press=after an operator to repeat the last operand (5 + =→ 10) - Gray live preview above input;
⌫erases a digit
Math Engine
Trigonometry (degrees)
sin(30°) = 0.5 sin(deg(30)) = 0.5
Scientific functions
sqrt, sin, cos, tan, asin, acos, atan, sinh, cosh, tanh, exp, ln, log, log2, abs, sign, round, floor, ceil, cbrt, hypot, mod, deg, rad
sqrt(16) = 4 log(1000) = 3 2^10 = 1024
Unit conversion
100 km to mi = 62.14 25 °C to °F = 77 5 kw to w = 5000 2 a to ma = 2000 1 mol → mmol = 1000 (2+3) km/h → mph
Supports length, area, volume, mass, temperature, speed, time, and a full set of SI units: ampere(a/ma/µa/ka), mole(mol/mmol/kmol), candela(cd), hertz(hz/kHz/MHz/GHz), newton(n/kN/mN), watt(w/kW/mW/GW), coulomb(c/mC/µC/kC), volt(v/mV/kV/µV), farad(f/mF/µF/nF/pF), ohm(Ω/ω/ohm, kilo kΩ/kω/kohm, milli mΩ/mω/mohm), weber(wb), tesla(mt/µt/nt/kt), henry(mh/µh/nh/kh), becquerel(bq), gray(gy/mGy), sievert(sv/msv), electron-volt(ev/keV/MeV/GeV), and more. `µ` (micro) and `u` are equivalent; units are case-insensitive. Very large/small results use scientific notation.
Theme & Display
Settings → Theme: Light / Dark / System. Orange highlights in dark mode, easy on the eyes.
Editor top bar "font size (A)": slider or A-/A+ (14–30), live preview and auto-save; title scales 1.4×.
Privacy & Security
- Zero permissions: no camera, contacts, storage, or network permission
- Offline: fully usable offline; no server collects notes
- No account: open and use
- No ads: open and use; no ads
- On-device only
FAQ
What can it calculate?
Arithmetic, parentheses, percentages, variables, trig in degrees, scientific functions, and unit conversion. Very large/small results use scientific notation.
How is it different from a notes app + calculator?
Normal tools keep notes and calculator apart, so you switch and copy-paste. MathNotes keeps math and text in one document, with inline results that recalculate with variables.
Are my notes safe?
Zero permissions, fully offline, no account — notes stay only on your device, never via any server or third-party SDK.
Can I change the font size?
Yes. Note body font size 14–30, applies instantly and is saved.
How do I convert units?
Use to (or →), e.g. 100 km → mi, 25 °C → °F.
Is calculator history saved?
Not in the current version; persistence is planned.