---
tags:
  - mathematics
  - basic-math
  - arithmetic
created: 2026-05-16
breadcrumb: "Mathematics > Basic math > Arithmetic & number basics"
---

# Arithmetic & number basics

> **Mechanism:** The four operations and what they preserve

## Items

- **Addition / subtraction** — Combine or remove quantities. Identity: 0. Inverse: negation.
- **Multiplication / division** — Scale or split. Identity: 1. Inverse: reciprocal.
- **Exponents** — a^n = a · a · … · a (n times). a^0 = 1, a^{−n} = 1/a^n.
- **Roots** — ⁿ√a is the inverse of a^n. √a means n = 2.
- **Order of operations** — PEMDAS / BODMAS — parentheses, exponents, multiplication, addition.
- **Fractions & percentages** — a/b, percentage = (part / whole) × 100.

## Related

- [[calculus-basics]]
- [[famous-math-equations]]