CRACK THE CODE · GRADE 4
Prehistoric Fossil Vault Code
Match the prehistoric fossils to their hidden values to crack the code on the paleontologist's field 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.×=
- 2.3+2=CODE 1
- 3.×=
- 4.100+=CODE 2
- 5.×−=
- 6.100+=CODE 3
- 7.×−=
- 8.3+2=CODE 4
- 9.(+)×=
- 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 paleontologists field crate.
Show answer key (for grown-ups)
Key: hexagon = 12 · triangle = 3 (hidden) · cross = 5 (hidden) · moon = 9 · heart = 13 · circle = 8 (hidden)
Every symbol is a whole number from 1 to 15.
Vault code: 5839