Why a Rp 100,000 PLN token never buys Rp 100,000 of electricity
PPJ comes out of the token first, PPN only touches certain customers, and the admin fee is charged per purchase. Here is the arithmetic, with two real receipts.
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Guides and explainers for text, code and image tools.
GPS coordinate formats explained: decimal degrees vs DMS
Why the same place has three different-looking coordinates, how to read each format, and how to convert between them without losing precision.
Read article →ASCII, Unicode and UTF-8: how text becomes bytes
Why an emoji sometimes turns into question marks, what 'UTF-8' on a save dialog actually means, and the mental model that makes encoding bugs make sense.
Read article →Understanding JSON: structure, common errors and formatting
JSON looks simple until a single misplaced comma breaks everything. Here is the full structure, the errors that bite most often, and how to read a parser message.
Read article →Binary, octal, hex and decimal: the same number, four ways
Why programmers keep switching number bases, what each one is good for, and a simple method to convert between them in your head.
Read article →The Caesar cipher and why classical ciphers are not security
A 2000-year-old cipher is the perfect way to learn how encryption thinks — and exactly why you must never trust it with anything real.
Read article →Morse code: how dots and dashes still carry messages
Born for the telegraph, Morse code survives because it needs almost nothing to work. Here is how it encodes letters and where it still matters today.
Read article →CSV, JSON and YAML: three data formats and when each fits
They all store structured data, but they are good at very different things. A practical comparison so you pick the right one and avoid painful conversions.
Read article →What is a hash? MD5, checksums and why you don't hash passwords with it
Hashing turns any input into a short fixed fingerprint. Here is what that is good for, what MD5 still does well, and the one job it must never be given.
Read article →Uppercase, Title Case or Sentence case: which to use?
Capitalisation changes tone and readability. A quick guide to the main styles and when each one fits.
Read article →What is Base64 and when should you use it?
Base64 turns binary data into safe, printable text. Here is what it does, where it shows up, and what it is not.
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