CRACK THE CODE · GRADE 4
Mars Rover Decoder
Solve the planetary symbol equations to discover the four-digit override code and boot up the stranded Mars rover.
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.×=
- 2.10−=CODE 1
- 3.(+)×=
- 4.3+2=CODE 2
- 5.×=
- 6.10−=CODE 3
- 7.×−=
- 8.×+=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 control panel of.
Show answer key (for grown-ups)
Key: heart = 3 · moon = 6 · triangle = 11 (hidden) · ring = 4 (hidden) · star = 14 · circle = 9 (hidden)
Every symbol is a whole number from 1 to 15.
Vault code: 4017