数学工具

Compute natural log (ln), common log (log₁₀), binary log (log₂), custom-base logarithms, and antilogs with change-of-base steps and verification.

Compute sin, cos, tan, csc, sec, cot, and inverse trig functions in degrees or radians with exact values and step-by-step work.

Calculate permutations nPr and factorials n! for ordered arrangements with formulas and step-by-step work.

Compute mean, median, mode, standard deviation, variance, quartiles, range, and more from any dataset with step-by-step formulas.

Fit a linear regression line to (x, y) data — slope, intercept, equation, correlation r, R², and predictions with step-by-step work.

Convert raw scores to z-scores and back using z = (x − μ) ÷ σ, with percentile and step-by-step work.

Find the mean, median, and mode of any data set with frequency tables, sorted data, and step-by-step work.

Count significant figures, round to N sig figs, and add, subtract, multiply, or divide with correct precision rules. Enter decimals, trailing zeros, or scientific notation. Free, instant, browser-based.

Calculate sample size for surveys, mean estimates, A/B tests, and two-group comparisons. Set confidence level, power, margin of error, and effect size. Step-by-step formulas. Free, browser-based.