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Notes for getting more out of the tools · calculations, metrics, CSS and work tips
Ad Metrics Made Simple | ROAS, CPA, CPC, CPM, CTR
What the five most-used performance marketing metrics: ROAS, CPA, CPC, CPM, and CTR: each measure, how they connect, and which to watch depending on your campaign goal.
Growth Rate, Fully Explained | Percentage Change, MoM, YoY, QoQ, WoW
Why growth rate and percentage change are really the same calculation, how MoM, YoY, QoQ, and WoW differ, and how to read growth correctly while avoiding the common traps: with worked examples.
How Korean Take-Home Pay Is Calculated | Insurance and Tax, Explained
Why gross salary and the amount that actually lands in your account differ, broken down through Korea's four major insurances and income tax, and how non-taxable amount, dependents, and withholding rate change your net pay.
px, rem, em, %, vw | Which CSS Unit to Use and When
What CSS absolute and relative units are each relative to, how they affect accessibility and responsiveness, and which unit to reach for in each situation.
The Power of Compounding | Compound Growth and Future Value
The difference between simple and compound growth, why compound growth and future-value projection are really the same calculation, and how rate and time change the outcome dramatically: with examples.
What Is JSON | A Data Format Anyone Can Understand
What JSON is and why it's everywhere, its basic structure and rules, the common syntax errors that break it, and why formatting and validation matter: explained without assuming you're a developer.
How QR Codes Work and How to Make Them Safely
How a QR code stores information, the difference between static and dynamic codes, balancing design against scannability, and what you must check before printing.
Merge, Split, Rotate, Delete PDF Pages | Do It Safely in the Browser
When each common PDF editing task: merge, split, rotate, delete pages: is actually needed, and why processing sensitive documents in the browser instead of uploading them to a server is the safer choice.
Character Limits for Social and Résumés | How to Count Correctly
Why character limits matter, the per-platform limits for X, Threads, Instagram and more, how counting works with and without spaces and for emoji, and how to hit a required length.