2nd/10_Wiki/Topic_JavaScript/JavaScript_Arithmetic.md

---
id: javascript-arithmetic
title: "JavaScript Arithmetic"
category: "Frontend"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["JS arithmetic", "arithmetic operators", "operator precedence", "modulus operator", "exponentiation operator", "increment decrement"]
duplicate_of: ""
source_trust_level: "B"
confidence_score: 0.89
created_at: 2026-06-23
updated_at: 2026-06-23
review_reason: ""
merge_history: []
tags: ["javascript", "js", "web", "frontend", "w3schools", "arithmetic", "operators"]
raw_sources: ["https://www.w3schools.com/js/js_arithmetic.asp"]
applied_in: []
github_commit: ""
---

# [[JavaScript Arithmetic]]

## 🎯 한 줄 통찰 (One-line insight)
Arithmetic operators perform arithmetic on numbers (literals or variables), with multiplication and division taking higher precedence than addition and subtraction. [S1]

## 🧠 핵심 개념 (Core concepts)
- **Arithmetic on numbers** — arithmetic operators perform arithmetic on numbers, which can be literals or variables. [S1]
- **Operands and operators** — the numbers in an arithmetic operation are called operands; the operation performed between two operands is defined by an operator. [S1]
- **Eight arithmetic operators** — `+`, `-`, `*`, `**`, `/`, `%`, `++`, `--`. [S1]
- **Modulus returns the remainder** — the modulus operator `%` returns the division remainder. [S1]
- **Exponentiation equals Math.pow** — `x ** y` produces the same result as `Math.pow(x, y)`. [S1]
- **Precedence and left-to-right** — multiplication and division have higher precedence than addition and subtraction; operations of equal precedence are computed left to right; parentheses override precedence. [S1]

## 🧩 추출된 패턴 (Extracted patterns)
- **Operate over literals or variables** — the operands of an arithmetic expression can be literals (`100 + 50`), variables (`a + b`), or sub-expressions (`(100 + 50) * a`). [S1]
- **Increment/decrement in place** — `x++` raises and `x--` lowers a variable by one. [S1]
- **Force evaluation order with parentheses** — wrap a lower-precedence operation in `()` to make it run first. [S1]

## 📖 세부 내용 (Details)
**JavaScript Arithmetic Operators** [S1]
Arithmetic operators perform arithmetic on numbers (literals or variables):

| Operator | Description |
|----------|-------------|
| + | Addition |
| - | Subtraction |
| * | Multiplication |
| ** | Exponentiation (ES2016) |
| / | Division |
| % | Modulus (Remainder) |
| ++ | Increment |
| -- | Decrement |

**Arithmetic Operations** [S1]
A typical arithmetic operation operates on two numbers. The two numbers can be literals:
```javascript
let x = 100 + 50;
```
or variables:
```javascript
let x = a + b;
```
or expressions:
```javascript
let x = (100 + 50) * a;
```

**Operators and Operands** [S1]
The numbers (in an arithmetic operation) are called operands. The operation (to be performed between the two operands) is defined by an operator.

**Adding** [S1]
```javascript
let x = 5;
let y = 2;
let z = x + y;
```

**Subtracting** [S1]
```javascript
let x = 5;
let y = 2;
let z = x - y;
```

**Multiplying** [S1]
```javascript
let x = 5;
let y = 2;
let z = x * y;
```

**Dividing** [S1]
```javascript
let x = 5;
let y = 2;
let z = x / y;
```

**Remainder** [S1]
The modulus operator (`%`) returns the division remainder. The result of a modulo operation is the remainder of an arithmetic division.
```javascript
let x = 5;
let y = 2;
let z = x % y;
```

**Incrementing** [S1]
The increment operator (`++`) increments numbers.
```javascript
let x = 5;
x++;
let z = x;
```

**Decrementing** [S1]
The decrement operator (`--`) decrements numbers.
```javascript
let x = 5;
x--;
let z = x;
```

**Exponentiation** [S1]
The exponentiation operator (`**`) raises the first operand to the power of the second operand.
```javascript
let x = 5;
let z = x ** 2;
```
`x ** y` produces the same result as `Math.pow(x, y)`:
```javascript
let x = 5;
let z = Math.pow(x,2);
```

**Operator Precedence** [S1]
Operator precedence describes the order in which operations are performed in an arithmetic expression. Multiplication and division have higher precedence than addition and subtraction:
```javascript
let x = 100 + 50 * 3;
```
Parentheses can change the order — operations inside parentheses are computed first:
```javascript
let x = (100 + 50) * 3;
```
When many operations have the same precedence (like addition and subtraction or multiplication and division), they are computed from left to right:
```javascript
let x = 100 + 50 - 3;
```
```javascript
let x = 100 / 50 * 3;
```

## 🛠️ 적용 사례 (Applied in summary)
The page's own snippets are the canonical applied examples — adding/subtracting/multiplying/dividing into `z`, taking a remainder with `%`, incrementing/decrementing, exponentiating with `**` vs `Math.pow`, and demonstrating precedence with and without parentheses. No external project/commit applications found in the source.

## 💻 코드 패턴 (Code patterns)
Operate over two variables:
```javascript
let x = 5;
let y = 2;
let z = x % y;
```
Exponentiate (two equivalent forms):
```javascript
let z = x ** 2;
let z = Math.pow(x,2);
```
Override precedence with parentheses:
```javascript
let x = (100 + 50) * 3;
```

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
No contradictions found in the source. The source notes the exponentiation operator `**` was introduced in ES2016, which is the relevant version context.

## ✅ 검증 상태 및 신뢰도
- **상태:** draft
- **검증 단계:** conceptual (실제 적용 사례 발견 시 applied/validated로 승격 가능)
- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
- **신뢰 점수:** 0.89
- **중복 검사 결과:** 신규 생성 (New discovery)

## 🔗 지식 그래프 (Knowledge Graph)
- **상위/루트:** [[JavaScript Tutorial]]
- **관련 개념:** [[JavaScript Operators]], [[JavaScript Assignment]], [[JavaScript Types]], [[JavaScript Comparisons]]
- **참조 맥락:** Referenced whenever computing numeric values or reasoning about evaluation order in expressions.

## 📚 출처 (Sources)
- [S1] W3Schools — JavaScript Arithmetic — https://www.w3schools.com/js/js_arithmetic.asp

## 📝 변경 이력 (Change history)
- 2026-06-23: Initial draft synthesized from the W3Schools "JavaScript Arithmetic" page (Astra wiki-curation, P-Reinforce v3.1 format).