CRACK THE CODE · GRADE 4
Fossil Lab Cipher
Solve the mathematical equations using the dinosaur footprint, tooth, and fossilized leaf symbols to find the combination for the heavy security crate.
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 15. 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.×+=CODE 1
- 3.100+=
- 4.(−)×=CODE 2
- 5.10−=
- 6.3+2=CODE 3
- 7.×=
- 8.3+2=CODE 4
- 9.100+=
- 10.×−=
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 heavy steel security.
Show answer key (for grown-ups)
Key: ring = 8 · square = 6 · triangle = 4 (hidden) · moon = 10 (hidden) · hexagon = 11 (hidden) · circle = 12
Every symbol is a whole number from 1 to 15.
Vault code: 8628