CRACK THE CODE · GRADE 4
Crack the Vault Code
Someone locked the vault with a 4-digit code. Work out what each shape is worth and crack it.
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.×−=
- 4.×=CODE 2
- 5.(−)×=
- 6.(+)×=CODE 3
- 7.×=
- 8.×+=CODE 4
- 9.3+2=
- 10.100+=
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 vault.
Show answer key (for grown-ups)
Key: moon = 15 (hidden) · heart = 12 (hidden) · pentagon = 5 · circle = 14 (hidden) · square = 3 · ring = 13
Every symbol is a whole number from 1 to 15.
Vault code: 7248