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Learn Advanced Arithmetic | Numbers
Data Types in Python

Advanced Arithmetic

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Learn how Python handles floor division and modulo (including negative numbers) and explore the math module for common numeric operations.

Floor Division (//)

Returns the floor of the exact quotient, meaning it rounds the result down.

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print(7 // 3) # 2 print(-7 // 3) # -3 (floors down: -2.333... → -3)

Why it matters: indexing chunks/pages, time splitting (hours from seconds), and any "how many full groups fit" calculation.

Modulo %

Returns the remainder of division. In Python, the remainder always has the same sign as the divisor.

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print(7 % 3) # 1 print(-7 % 3) # 2 print(7 % -3) # -2

Why it matters: "every Nth" item, wrap-around (e.g., clock arithmetic), cycling through buckets.

Examples:

  • Keeping track of hours on a clock14 % 12 = 2 - (2 PM);
  • Selecting every 3rd item in a list → if i % 3 == 0:.

Quick Note on Rounding

Built-in round(x, ndigits) uses "round half to even".

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print(round(2.5), round(3.5)) # 2 4 print(round(2.675, 2)) # 2.67 (binary float nuance)

The math Module

Import once and access many handy functions/constants.

123456
import math print(math.floor(2.9), math.ceil(2.1), math.trunc(-2.9)) # 2 3 -2 print(math.sqrt(9)) # 3.0 print(math.pi, math.e) # 3.14159... 2.71828... print(math.isfinite(1.0), math.isfinite(float('inf'))) # True False

1. What value will this code output?

2. What value will this code output?

3. Which call returns -3?

question mark

What value will this code output?

Select the correct answer

question mark

What value will this code output?

Select the correct answer

question mark

Which call returns -3?

Select the correct answer

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Section 1. Chapter 3

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Section 1. Chapter 3
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