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Features

Clues about the hundreds, tens and ones digits: sums, products, odd and even, greater and less
A board to cross out the digits that cannot be in each place
A helper for one clue, and a wrong try to disprove
Exactly one code works on every page, and every clue is needed
Support, on-level, and challenge pages
Color and black-and-white versions
Answer keys included

Skills Covered

Use clues to narrow down possibilities
Reason about hundreds, tens and ones digits
Use multiplication facts to find digit pairs

Tell odd and even numbers apart
Compare 3-digit numbers
Find a counterexample to test a claim

How to Use This Pack

Each page is one vault with a 3-digit code. Students read every clue, cross out the digits that cannot be in each place on the board, write each pair of digits that fits one clue, and find the one code that passes every clue. Then they show why a wrong try fails. Pages 1 to 4 are on grade level with four clues; pages 5 and 6 are support pages with three clues, and clue 1 already crossed out on the board as an example; pages 7 and 8 are a challenge with five clues, a why question, and a claim to disprove with a code of their own.

In the Classroom

Work the first clue together on the board and talk about which clue leaves the fewest choices. Students can solve in pairs, then check each other's code against every clue and tick the boxes.

At Home

Ask your child which clue they started with and why. When they find the code, have them read every clue again and tick each one it passes.

Tips for Success

Start with the clue that leaves the fewest choices
Cross out digits on the board as you go
A clue about one place tells you about one row of the board
Check your code against every clue before you write it in

Common Core Standards Alignment

This pack supports the following Common Core State Standards for Mathematics:

2.OA.C.3 Decide if up to 20 objects are odd or even (match them in twos or skip count by 2s); write evens as doubles.
2.NBT.A.4 Compare three-digit numbers by looking at the value of each place, and record the result with >, = or <.
3.OA.C.7 Multiply and divide to 100 fluently with strategies, and by year's end instantly recall every product of two single-digit numbers.

Crack the Vault: 3-Digit Code Logic Puzzles

3rd Grade

Logic puzzles where a vault opens with a 3-digit code and every clue about its digits is true. Students use place value, odd and even numbers and multiplication facts to cross out what cannot be, find the one code that works and prove a wrong try wrong.

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What’s Included

8 printable worksheets, one vault puzzle per page
3 difficulty levels: On Level (pages 1–4), Support (pages 5–6), Challenge (pages 7–8)
Color and printer-friendly black-and-white versions
Answer keys for all 8 worksheets

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Free to print and share

This worksheet is free to download, print, copy, and hand out in your classroom or at home. You do not need to create an account, and there are no watermarks on the PDF.