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CRACK THE CODE · GRADE 2

The Cretaceous Code Breaker

Find the secret numbers hidden behind the fossil shapes to unlock the secure dinosaur egg incubator.

Each shape stands for a number. 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.

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The key

=8
=2
=1
=6
=7

Every symbol is a whole number from 1 to 10. A number in front of a shape means multiply: 2 stars = 2 x star.

Crack these

  1. 1.2+=
  2. 2.2+=CODE 1
  3. 3.3−=
  4. 4.2−=CODE 2
  5. 5.+−=
  6. 6.3=CODE 3
  7. 7.+−=
  8. 8.3=CODE 4
  9. 9.?+=13Which shape?
  10. 10.?+=8Which shape?

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 egg.

Show answer key (for grown-ups)

Key: triangle = 8 · ring = 2 · heart = 1 · cross = 6 · lightning bolt = 7

Every symbol is a whole number from 1 to 10.

1.2 x heart + triangle10
2.2 x ring + cross10
3.3 x triangle - ring22
4.2 x lightning bolt - ring12
5.lightning bolt + heart - ring6
6.3 x lightning bolt21
7.lightning bolt + heart - triangle0
8.3 x triangle24
9.? + cross = 13lightning bolt
10.? + ring = 8cross

Vault code: 0214

About Crack the Code

Crack the Code is early algebra without the letters: a key maps shapes to numbers, and the kid substitutes, computes, and — from grade 3 up — deduces hidden values from shape equations before they can solve anything. Grade 2 practices addition, subtraction, and multiplying by 2 and 3. Every sheet has exactly one right key and one right code.

It's one of three things Math Mysteries makes, free and printable, personalized to what your kid is into: a full math mystery whodunit, a Lab Work sheet of multi-step word problems, or a Crack the Code sheet like this one. Browse free printable worksheets by grade, skill, and theme.

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