Mathematical Tools
Percentage Calculator Guide: Four Core Formulas and Where People Get It Wrong
The four percentage problem types, percentage points vs percentages, the stacked discount problem, and tipping math shortcuts.
•8 min read
Mathematical Tools
Explore our collection of articles and guides in this category.
6 articles
Mathematical Tools
Fraction Calculator Guide: The Four Operations Step by Step and Real-World Applications
Adding, subtracting, multiplying, and dividing fractions with worked examples, fraction/decimal/percent conversion table, and the Python Fraction class.
•9 min read
Mathematical Tools
GPA Calculator Guide: How Weighted Averages Work and What GPAs Actually Signal
The GPA formula (weighted average by credit hours), the full 4.0 scale table with letter grades, worked calculation example, and what GPAs mean to employers.
•9 min read
Mathematical Tools
Random Number Generation Guide: PRNG, CSPRNG, and the 2008 Debian SSH Key Disaster
PRNG vs TRNG vs CSPRNG, the Mersenne Twister, why Math.random() is not cryptographically secure, and the Debian 2008 OpenSSL key generation bug.
•10 min read
Mathematical Tools
Scientific Calculator Guide: Logarithms, Trig in Radians vs Degrees, and PEMDAS Ambiguity
log vs ln distinction, sin(90) in radians ≠ 1 (the most common trig error), implied multiplication ambiguity in PEMDAS, and scientific notation EE key.
•9 min read
Mathematical Tools
Percentage Calculations Guide: Every Formula, Stacked Discounts, and Markup vs Margin
All four percentage problem types, why 50% off then 20% off is 60% total (not 70%), percentage points vs percent, and the markup vs margin denominator difference.
•9 min read