CRACK THE CODE · GRADE 8
The Coral Crypt Equations
Solve the algebraic symbol equations to find the hidden values of the starfish, trident, shell, and pearl, then use them to decode the combination to the ocean floor vault.
Each shape stands for a number. Work out the missing ones first, then solve the shape equations and read off the 4-digit code. Do it here or print the sheet — the answer key comes with it.
The key
Every symbol is a whole number from 1 to 30. A number in front of a shape means multiply: 2 stars = 2 x star. A small 2 after a shape means square it: star^2 = star x star. sqrt(shape) is the square root of that shape's value.
Find the missing values
Some shapes in the key are missing. Use these equations to work them out, then write them into the key. Take them in order.
Crack these
- 1.√()+=
- 2.√()+2=CODE 1
- 3.(+)2=
- 4.2+2=CODE 2
- 5.(+)2=
- 6.3−2+=CODE 3
- 7.3−=
- 8.3−=CODE 4
- 9.2−=
- 10.2−=
The vault code
Take the ones digit of your answers to problems 2, 4, 6, 8 (the ones tagged CODE 1–4), in that order. That opens the sunken brass treasure.
Show answer key (for grown-ups)
Key: hexagon = 14 (hidden) · lightning bolt = 19 (hidden) · circle = 25 (hidden) · ring = 12 (hidden) · moon = 26 · triangle = 7
Every symbol is a whole number from 1 to 30.
Vault code: 9974