Operators in JavaScript

1. What are Operators in JavaScript?

Operators are symbols used to perform operations on values (called operands).
Example:

let result = 10 + 5;

Here:

• 10 and 5 → operands
• + → operator

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1. Types of Operators (Basic Idea)

Some common operators:

• Arithmetic → +, -, *, /
• Assignment → =, +=
• Comparison → ==, ===
• Logical → &&, ||

Now we focus on Arithmetic operators (+ and -)

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1. Addition (+) Operator

How it works:

1. If both values are numbers → addition
2. If any one is string → convert to string
3. Then join (concatenate)

Examples

Number + Number

javascript
console.log(10 + 5); // 15

String + String

console.log("Hello" + " JS"); // "Hello JS"

String + Number

console.log("10" + 5); // "105"

Number + String

console.log(10 + "5"); // "105"

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1. Subtraction (-) Operator

How it works:

1. Convert both values to numbers
2. Perform subtraction
3. If not possible → NaN

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Examples

Number - Number

console.log(10 - 5); // 5

⚠️ String - Number

console.log("10" - 5); // 5

Number - String

console.log(10 - "5"); // 5

String - String

console.log("10" - "5"); // 5

Invalid String

console.log("Hello" - 5); // NaN

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1. Final Difference

Operator	Behavior
+	Can add OR join strings
-	Always numeric subtraction

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1. Easy Memory Trick

console.log("5" + 5); // "55"
console.log("5" - 5); // 0

+ → string joins
- → number math only