How it works
Every box of the message has a number. Pupils work out that calculation, find the answer in the code and write its letter in the box.
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Teaching guide: getting the most out of maths code breakers
A maths code breaker turns a page of calculations into a puzzle: every letter of a message hides behind a sum, and only pupils who work it out correctly can read it. This free maths code breaker worksheet generator makes A4 worksheets of addition, subtraction, times tables, division and mixed operations for Grades 2 to 6, with riddles, number jokes, sayings and true facts written in English, and an answer key with every answer and the message.
- For
- Elementary 2nd, 3rd, 4th, 5th, 6th (ages 7-11)
- Subject
- Mathematics › Arithmetic
- Includes
- Student sheet and answer key
- Format
- A4, to print or save as PDF; new exercises every time
- Price
- Free, no sign-up
- Available in
- Catalan, Spanish, English
Student worksheet 
Answer key Self-checking
If the message makes no sense, one of the answers is wrong: pupils know where to look again without waiting for marking.
Decoy letters
The code also lists numbers and letters that are not in the message, so it cannot be cracked by guessing what is left.
Repeated letters
A letter that appears several times gets different calculations with the same answer: pupils practise the maths, not their memory.
Grades 2 to 6
Adding and subtracting to 20, 100 and 1000, the times tables, exact division and all four operations mixed.
Custom level
Choose the largest number, carrying or borrowing, the highest times table and the length of the message, or let each code breaker come out at random.
Frequently asked questions about maths code breakers
What is a maths code breaker?
It is a message hidden with numbers. Each letter has a number in the code and each box of the message has a calculation: when pupils work it out, the answer tells them which letter goes there. At the end they read the answer to a riddle, a joke, a saying or a fact. Some teachers call them maths cryptograms or secret code worksheets.
Which grades are these worksheets for?
Grades 2 to 6 (Years 3 to 7). Level 1 practises adding and subtracting to 20 and the 2, 5 and 10 times tables (Grade 2); levels 2 and 3 practise calculations to 100, every times table and the matching divisions (Grades 3 and 4); level 4 uses three-digit numbers, two digits × one and exact divisions of three-digit numbers (Grades 4 to 6).
Can one letter come up with the same calculation twice?
Not while the level has enough different calculations with that answer: a letter that appears four times gets four different calculations. Each letter of the message has its own number, and the code adds a few decoy numbers with letters that are not in the message.
Can I choose how big the numbers are?
Yes. Besides the four levels, each operation has a Custom level: the largest number (20 to 1000), whether additions and subtractions need carrying or borrowing, the highest times table for multiplication and division, and a short, medium or long message. The Random level makes every code breaker different within the limits you set.
Do the messages repeat?
Not within one exercise: each code breaker has its own message. There are riddles, number jokes, sayings, true facts about animals and space, and words of encouragement, written for each language.
What is in the answer key?
The answer to every calculation and the whole message written in the boxes, so marking takes a moment. Click Print and choose "Answer key" or "Worksheet and answer key"; you can also save it as a PDF.
Can I mix code breakers with other exercises?
Yes. Add exercises of different operations and levels to the same worksheet, combine them with column operations, mental maths drills or times tables worksheets and drag them wherever you like. More number puzzles are in number pyramids and magic squares and under maths worksheets.
Is any pupil data sent anywhere?
No. Worksheets are generated in your browser and templates are saved in your browser's memory.
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