Number-Based Codes
📋 What it is
Number codes map letters to numbers (A=1, B=2…) so messages become sequences of numbers.
🗣️ Coach says
Letters can hide as numbers. A=1, B=2, … Z=26 turns “HI” into “8 9”. Computers do this all the time (with a code called ASCII). Once letters are numbers, you can add maths tricks on top to encrypt further.
🧠 Memory hook
Letters → numbers (A=1…Z=26). Numbers can then be scrambled with maths.
😂 Giggle
Why did the secret message break up with the envelope?
It felt too sealed off from the world!
😲 Whoa!
Every letter you type is secretly a number to the computer — “A” is 65 in the ASCII code — so all text is really numbers in disguise.
✅ Quick check: Using A=1…Z=26, decode “3 1 20”.
Say your answer out loud first — then reveal.
“CAT” — 3=C, 1=A, 20=T.
Reversing the letter-to-number map decodes the message.
🧪 Try it! (2 minutes)
Encode your initials as numbers (A=1…) and have a friend decode them back to letters.