*Basic mathematics including operations like addition, subtraction, multiplication and division*

Arithmetic is a basic part of math that deals with common operations like addition, subtraction, multiplication and division. Players are generally expected to understand arithmetic and therefore it is commonly used as a device facet in games.

Live Examples:**- Poly Sticks:** Arithmetic, Geometry

Arithmetic is required to solve algebraic puzzles, and most basic arithmetic can be presented in the form of an equation. For example, "What is 5 × 3?" is algebraically expressed as "5 × 3 = 𝑥", where you need to solve for 𝑥. Yet, more people will understand the lingual form than the algebraic one.

The distinction between symbols and numbers is important here. Arithmetric is focused on concrete values, where a player must arrive at a definite value. Algebra steps into the abstract, giving a way to write the thought process and deal with more complex situations.

We're drawing a distinction for the purpose of complexity. As long as you can express a numeric puzzle in simple language, it tends to be arithmetic, and thus its complexity is lower than an algebraic puzzle. For example, "If a bus has 10 rows of 4 seats, how many buses will it take to drive 100 people to the fair?" A player without knowledge of algebra can solve these types of problems, even if the expression "𝑥 × (10 × 4) = 100" is foreign to them.

The history of arithmetic is both interesting and a good place to get numeric puzzle ideas. As numbers evolved they've left a trail of curious symbols and mechanisms — all great source material. Plus, they can lend a thematic flair to your games.

If you have any questions, need an example, or want clarification, then let me know. Ask on Discord or Twitter.

Assume everything in this reference is a working draft, there's prone to be some mistakes and inconsistencies. I figure it's best to publish and get feedback rather than write for years in secret. The terms will change, the structure will shift, and the bugs will be chased out. It'll take a while.