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🐍 Python Basics Topic 7 / 100

⏱ 9 min read

Numbers: int and float

Working with whole numbers and decimals. Every arithmetic operation Python can do — explained simply with real examples.

"Numbers are the language of logic. Master them in Python and every door in data, finance, science, and AI opens a little wider."

— ShurAI

Two Types of Numbers in Python

Python has two main number types. Understanding the difference is the first step:

🔢

int

Integer

Whole numbers — no decimal point. Can be positive, negative, or zero.

              5  ·  -3  ·  0  ·  1000  ·  -99
            

🔣

float

Floating Point

Decimal numbers — have a dot. Used for measurements, prices, percentages.

              3.14  ·  -0.5  ·  9.99  ·  100.0
            

python

# int — whole numbers
age        = 22
temperature = -5
population = 1400000000

# float — decimal numbers
height     = 5.9
price      = 299.99
pi         = 3.14159

# Check the type
print(type(age))     # <class 'int'>
print(type(price))   # <class 'float'>

Simple Rule to Remember

If it has a dot — it is a float. If it does not — it is an int. Even 5.0 is a float, not an int, because of the dot.

Arithmetic Operators — Python's Calculator

Python can do all the maths you know, plus a couple of extras that are incredibly useful in programming:

Symbol	Operation	Example	Result
+	Addition	10 + 3	13
-	Subtraction	10 - 3	7
*	Multiplication	10 * 3	30
/	Division	10 / 3	3.333... (float)
//	Floor Division	10 // 3	3 (drops decimal)
%	Modulo (remainder)	10 % 3	1 (leftover)
**	Exponent (power)	10 ** 3	1000 (10³)

python — all operators in action

a = 10
b = 3

print(a +  b)   # 13   — addition
print(a -  b)   # 7    — subtraction
print(a *  b)   # 30   — multiplication
print(a /  b)   # 3.3333333333333335 — always float
print(a // b)   # 3    — floor division, drops decimal
print(a %  b)   # 1    — remainder after 10 ÷ 3
print(a ** b)   # 1000 — 10 to the power of 3

Floor Division and Modulo — Simply Explained

These two confuse beginners the most. Here is the simplest way to understand them — think about sharing things equally:

//

Floor Division

Question: If you have 10 mangoes and share equally among 3 people, how many does each person get?

Answer: 3 (the leftover 1 is ignored)

10 // 3 → 3

%

Modulo

Question: Same 10 mangoes, 3 people get 3 each (total 9). How many mangoes are LEFT over?

Answer: 1 (10 - 9 = 1 remaining)

10 % 3 → 1

Modulo's Most Common Use

Checking if a number is even or odd: number % 2 == 0 means even (no remainder). number % 2 == 1 means odd. You will use this constantly in real programs.

python — even or odd checker

number = 7

if number % 2 == 0:
    print(f"{number} is even")
else:
    print(f"{number} is odd")

# Output: 7 is odd

Order of Operations — BODMAS

Python follows the same order of operations you learned in school — Brackets first, then powers, then multiply/divide, then add/subtract. Always use brackets when in doubt:

python

print(2 + 3 * 4)      # 14 — multiply first, then add
print((2 + 3) * 4)    # 20 — brackets first
print(2 ** 3 + 1)     # 9  — power first (2³=8), then +1
print(10 / 2 + 3)     # 8.0 — divide first, then add

Mixing int and float

When you do arithmetic with an int and a float together, Python always gives back a float. This is by design — Python wants to make sure no precision is lost:

python

print(5 + 2.0)    # 7.0   — float wins
print(10 * 3.0)   # 30.0  — float wins
print(7 / 2)      # 3.5   — division ALWAYS gives float
print(7 // 2)     # 3     — floor division gives int

Converting Between int and float

You can manually convert between the two types using int() and float():

python

# float → int (drops the decimal, does NOT round)
print(int(9.9))    # 9  — decimal part is cut off
print(int(3.1))    # 3  — NOT rounded to 3

# int → float
print(float(5))    # 5.0
print(float(100))  # 100.0

# string → int or float (useful when reading user input)
print(int("42"))      # 42
print(float("3.14"))  # 3.14

int() Truncates, Does Not Round

int(9.9) gives 9, not 10. It simply cuts off everything after the decimal point. To round properly, use Python's built-in round() function: round(9.9) gives 10.

Useful Number Functions

python

# round() — round to nearest whole number or decimal places
print(round(3.7))       # 4
print(round(3.14159, 2)) # 3.14 — keep 2 decimal places

# abs() — absolute value (removes negative sign)
print(abs(-50))    # 50
print(abs(50))     # 50

# max() and min() — largest and smallest of given values
print(max(10, 50, 30))   # 50
print(min(10, 50, 30))   # 10

# pow() — same as **
print(pow(2, 8))    # 256 — 2 to the power of 8

Real World Example — Bill Calculator

Here is a practical program that uses almost every number concept from this lesson:

python — restaurant bill calculator

# Restaurant bill calculator

food_price    = 450.00   # float — price in rupees
drinks_price  = 120.00
people        = 4         # int — number of people
gst_percent   = 18        # int — tax percentage

# Calculate total
subtotal  = food_price + drinks_price
gst       = (subtotal * gst_percent) / 100
total     = subtotal + gst
per_person = round(total / people, 2)

print(f"Subtotal  : ₹{subtotal}")
print(f"GST (18%) : ₹{gst}")
print(f"Total     : ₹{total}")
print(f"Per person: ₹{per_person}")

output

Subtotal  : ₹570.0
GST (18%) : ₹102.6
Total     : ₹672.6
Per person: ₹168.15

"Every app that handles money, every game that tracks score, every science program that measures data — they all start here, with numbers."

— ShurAI

🧠 Quiz — Question 1

What is the difference between 7 / 2 and 7 // 2 in Python?

🧠 Quiz — Question 2

What does 10 % 3 return?

🧠 Quiz — Question 3

What is the output of print(2 + 3 * 4)?

🧠 Quiz — Question 4

What does int(9.9) return in Python?

🧠 Quiz — Question 5

Which operator is used to raise a number to a power in Python? (e.g. 2 to the power of 5)