Scientific Calculator

In DEG mode, angles are in degrees (full circle = 360°). In RAD mode, angles are in radians (full circle = 2π ≈ 6.28). Scientific and programming contexts typically use radians; everyday use typically uses degrees.

A logarithm answers: 'what power do I raise the base to, to get this number?' log₁₀(1000) = 3 because 10³ = 1000. The natural log (ln) uses base e ≈ 2.718 and is fundamental in calculus and growth models.

e ≈ 2.71828 is a mathematical constant that is the base of the natural logarithm. It appears naturally in compound interest, population growth, radioactive decay, and probability distributions (the bell curve). Like π, it is irrational and transcendental.

Factorial n! = n × (n−1) × (n−2) × ... × 1. For example, 5! = 120. It counts the number of ways to arrange n items. 0! = 1 by definition. Factorials grow extremely fast: 20! ≈ 2.4 × 10¹⁸.