Numbers and operators

Basics8 min readLesson 3 of 8

Python stores whole numbers as integers (int) and decimal numbers as floats (float). The usual operators are +, -, *, and /, with // for floor division, % for the remainder, and ** for powers. Bills, marks, averages, and measurements all depend on these rules.

python

whole = 17
part = 5
print(whole + part)
print(whole // part)
print(whole % part)

Output

22
3
2

3.1 Order of operations Arithmetic follows the order you learned in school: Powers Multiplication and division Addition and subtraction Parentheses let you state the order yourself, so (2 + 3) * 4 runs the addition first. 3.2 Division and types / always returns a float, even when the numbers divide evenly: 8 / 2 gives 4.0 . // returns how many whole groups fit, rounded down. % returns what is left. Mixing an int and a float produces a float . A total built from a price with paise can come back with a decimal part for that reason.

python

print(2 + 3 * 4)
print((2 + 3) * 4)
print(8 / 2)
print(8 // 3)
print(8 % 3)

Output

3.3 Common mistake Expecting / to return a whole number leads to confusing output. Using // when a decimal average is needed has the opposite problem. For example, 7 // 2 is 3, while 7 / 2 is 3.5, so choose the operator that matches the question. When a calculation mixes several operators, add parentheses around the part you want first. Use round(value, 2) when a result should be rounded to two decimal places.

python

price = 19.99
quantity = 3
total = price * quantity
print(type(total))
print(round(total, 2))

Output

<class 'float'>
59.97

3.4 Practice Write a bill for three items with an integer price for each. Print the subtotal, the tax at 5 percent, and the final total. Round the final total with round(final_total, 2) . Repeat the calculation with one price stored as a float and check whether the printed type changes.

in hinglish

Python poore numbers ko integer aur decimal wale numbers ko float ki tarah rakhta hai. Arithmetic ke liye operators hain: jod, ghatav, guna, baant, floor division, remainder aur power. Bill, marks aur average jaise calculations inhi rules par chalte hain. Order of operations school jaisa hi hai: pehle power, phir multiplication aur division, phir addition aur subtraction. Parentheses se aap order badal sakte ho, isliye jahan confusion ho wahan bracket lagao. Normal division hamesha float deta hai, chahe 8 ko 2 se baantne par 4.0 aaye; floor division poore groups ginata hai aur remainder bacha hua hissa deta hai. Ek integer aur ek float milane par result float banta hai. Exam mein pehle likho ki answer decimal chahiye ya poora, phir sahi operator chuno; paise wale total ko do decimal tak round karo aur mixed operators ke beech parentheses lagao.