Computer Science: Arithmetic, Relational & Boolean Operations

🔢 3.2.3 Arithmetic Operations

Arithmetic operations are like the math you already know — adding, subtracting, multiplying, and dividing numbers! These help computers do calculations.

✨ Main Operations

Addition (+) → Puts numbers together.
5 + 3 = 8 🍎🍎🍎🍎🍎 + 🍎🍎🍎 = 8 apples!
Subtraction (-) → Takes one number away from another.
9 - 4 = 5 🎈🎈🎈🎈🎈
Multiplication (*) → Repeats addition.
6 * 2 = 12 (6 groups of 2!)
Real Division (/) → Splits things evenly, can give decimals.
10 / 4 = 2.5 🍕 (2 full pizzas and half of one!)
Integer Division (//) → Splits things but only keeps the whole number.
11 // 2 = 5
Remainder (% or MOD) → What’s left over after dividing.
11 % 2 = 1 (One left over!)

💡 Example with clocks: Clocks use “modular arithmetic.” If it’s 11 o’clock and you add 3 hours → it’s 2 o’clock!

(11 + 3) % 12 = 2 ⏰

⚖️ 3.2.4 Relational Operations

Relational operations help computers compare values — to check if one is bigger, smaller, or equal to another. The answer is always True or False.

Operation	Meaning	Example	Result
==	Equal to	5 == 5	True ✅
!=	Not equal to	5 != 3	True ✅
<	Less than	2 < 5	True ✅
>	Greater than	7 > 10	False ❌
<=	Less than or equal to	3 <= 3	True ✅
>=	Greater than or equal to	6 >= 4	True ✅

📘 Example in Python:

if age >= 18:
print("You can vote!")

🧠 3.2.5 Boolean Operations

Boolean operations help computers make decisions using True and False values. They combine or change conditions to decide what should happen next.

Operator	Meaning	Example	Result
NOT	Turns True → False	NOT True	False ❌
AND	True if both are True	(5>2) AND (3<8)	True ✅
OR	True if at least one is True	(5<2) OR (3<8)	True ✅

📘 Example in Python:

if (age >= 18) AND (citizen == True):
print("You are eligible to vote.")

🔍 Another example:

if (score > 50) OR (NOT submitted_late):
print("Pass 🎉")