Education

Compute n! (factorial), n!! (double factorial), and !n (subfactorial) with BigInt precision, digit counts, and trailing-zero analysis.

Compute the nth Fibonacci number, generate the first n terms, or check whether a number is Fibonacci. BigInt precision with golden-ratio convergence analysis.

Calculate the final exam score you need from your current grade, final weight, and target course grade.

Free online fraction calculator supporting arbitrary-operand add/sub/mul/div with integer powers. Natively parses mixed numbers, repeating decimals (0.(3)), percents, and Unicode fraction characters (½ ¼ ⅓). BigInt exact arithmetic with auto-reduce, simultaneous display of improper/mixed/repeating-decimal/percent/LaTeX forms, and step-by-step LCM/combine/GCD explanation plus pie-chart and number-line visuals.

Compute n! (factorial), n!! (double factorial), and !n (subfactorial) with BigInt precision, digit counts, and trailing-zero analysis.

Compute the nth Fibonacci number, generate the first n terms, or check whether a number is Fibonacci. BigInt precision with golden-ratio convergence analysis.

Calculate the final exam score you need from your current grade, final weight, and target course grade.

Free online fraction calculator supporting arbitrary-operand add/sub/mul/div with integer powers. Natively parses mixed numbers, repeating decimals (0.(3)), percents, and Unicode fraction characters (½ ¼ ⅓). BigInt exact arithmetic with auto-reduce, simultaneous display of improper/mixed/repeating-decimal/percent/LaTeX forms, and step-by-step LCM/combine/GCD explanation plus pie-chart and number-line visuals.

All-in-one geometry calculator for 25 common 2D shapes and 3D solids — area, perimeter, volume, surface area. Reverse-solve from any known value, with parameter-responsive SVG diagrams, substituted formula steps, per-field unit conversion, and adjustable significant figures / π precision.

Factor integers into primes, list all divisors with factor pairs, and test primality — with step-by-step process and large number support.

Calculate GCD and LCM for multiple integers with Extended Euclidean Algorithm and Bézout's identity. Shows step-by-step Euclidean and prime factorization methods.

Calculate GPA from course credits and letter grades with weighted grade points and total credits.

Calculate weighted course grades from assignments, quizzes, midterms, and finals.

Local matrix calculator with multi-matrix expressions, exact fraction arithmetic, step-by-step teaching, LU/QR/Cholesky decompositions, 2×2/3×3 eigenvalues, and Excel/CSV/MATLAB/NumPy/LaTeX paste. No login, default no ad scripts, no upload.

Local maze generator: 3 algorithms (Recursive Backtracker / Prim / Kruskal), reproducible seeds, A4 printable with optional answer page, QR code for mobile sharing, daily challenge seed. Includes dead-end highlight, shortest-path solver, PNG/SVG export. No login, default no ad scripts, no upload.

Education-grade + research-grade descriptive statistics calculator: 13 core statistics (mean, median, mode, variance, SD, range, quantiles, IQR, ...) + 3 education modes (China high school / international / research) + denominator toggle (n-1 / n) + 3 SVG charts (histogram / box plot / QQ-plot) + normality tests (Jarque-Bera + D'Agostino K²) + 3-method outlier detection + multi-delimiter paste + 4-format export. Welford+Kahan compensated numerical core.

Local Sudoku generator and game with real 5-level technique-based difficulty (Easy/Medium/Hard/Expert/Evil), triple highlighting (row-col-box/same-number/selected), auto-pencil candidates, 4-stage progressive hints, local best times, daily puzzle, URL sharing, 200-step undo/redo, dark mode. Mobile-friendly 44px touch targets. No login, default no ad scripts, no upload, default no third-party analytics.

Enter 4 playing cards (A/J/Q/K letters or 1–13 numbers) and see every expression that makes 24. Features exact rational arithmetic (catches fraction solutions like 8÷(3−8÷3)), equivalence dedup, bracket-minimized display, custom target, random deal, and classic hard-case presets. Works on desktop and mobile.