CRACK THE CODE · GRADE 3
Mermaid Reef Secret Code
Use your math skills to figure out the shape values and unlock the pearl chest resting on the ocean floor.
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 12. A number in front of a shape means multiply: 2 stars = 2 x star.
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.×=
- 4.×+=CODE 2
- 5.2+=
- 6.++=CODE 3
- 7.×+=
- 8.×−=CODE 4
- 9.10+=
- 10.3−=
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 pearl chest.
Show answer key (for grown-ups)
Key: square = 7 · heart = 10 (hidden) · moon = 3 · lightning bolt = 4 (hidden) · cross = 6 · circle = 2
Every symbol is a whole number from 1 to 12.
Vault code: 8235