Arithmetic operators
“Arithmetic operators perform basic mathematical operations like addition, subtraction, multiplication, and division.”
👉 Use image showing: + - * / % **
let a = 10, b = 3;
console.log("Addition:", a + b); // 13
console.log("Subtraction:", a - b); // 7
console.log("Multiplication:", a * b); // 30
console.log("Division:", a / b); // 3.33
console.log("Remainder:", a % b); // 1
console.log("Power:", a ** b); // 1000
console.log("Floor:", Math.floor(a/b)); // 3
Ok, but the number and string complain about what happened Number + String
Converts number to string and joins
let a = 10;
let b = "5";
let result = a + b;
console.log(result); // "105"
👉 Important: - (minus) is NOT like +
It always tries to convert values to numbers.
Subtraction
let a = 10;
let b = "5";
let result = a - b;
console.log(result); // "5"
❌ Invalid String
let a = "hello";
let b = 5;
console.log(a - b); // NaN
Assignment operators
“Assignment operators are used to assign and update values in variables.”
👉 Show:= += -= *= /= %=
```let x = 5;
x += 3; // x = x + 3 → 8
x -= 2; // 6
x *= 2; // 12
x /= 4; // 3
x %= 2; // 1
console.log(x);
Comparison Operators
- They are used to compare two values
- Result is always: true or false
Equal (==) – Loose Equality
console.log(5 == 5); // true
console.log(5 == "5"); // true
`Explanation:
Checks value only
Automatically converts type.
Strict Equal (===) – Strong Equality
console.log(5 === 5); // true
console.log(5 === "5"); // false
`✅ Explanation:
Checks value + type
No conversion
👉 number ≠ string.`
⚠️ Important Difference
console.log(0 == false); // true
console.log(0 === false); // false
👉 == converts → both become 0
👉 === checks type → different
Not Equal (!=)
console.log(5 != 3); // true
console.log(5 != "5"); // false
✅ Converts type like ==
Strict Not Equal (!==)
console.log(5 !== "5"); // true
console.log(5 !== 5); // false
✅ Checks value + type
Greater Than (>)
console.log(10 > 5); // true
console.log(5 > 10); // false
Less Than (<)
`
console.log(3 < 5); // true`
Greater Than or Equal (>=)
console.log(5 >= 5); // true
console.log(6 >= 5); // true
Less Than or Equal (<=)
`console.log(4 <= 5); // true
console.log(5 <= 5); // true`
⚠️ Tricky Cases (Very Important)
1. Null & Undefined
console.log(null == undefined); // true
console.log(null === undefined); // false
```plaintext
<u>2. Boolean Conversion</u>
console.log(true == 1); // true
console.log(false == 0); // true
<u>3. Empty String</u>
console.log("" == 0); // true
console.log("" === 0); // false
---------------------------------
**Logical Operator**s
👉 Used for **conditions**
let a = true, b = false;
console.log(a && b); // false
console.log(a || b); // true
console.log(!a); // false
✅ **Explanation:**
`&& → both true
|| → any one true
! → opposite`
----------------------------------
**Increment / Decrement**
Increase or decrease value.
let x = 5;
x++; // 6
x--; // 5
console.log(x);
**Prefix vs Postfix**
let a = 5;
console.log(++a); // 6 (first increase)
console.log(a++); // 6 (then increase)
---------------------------------------
**I can give a question for Increment / Decrement**
let i=4;
let j=5;
let result = i++ + --j + ++j -i++ -i++ ;
console.log(result);
console.log(i)
console.log(j)
--------------------
“Guess what the values of result, i, and j are.”
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