The worksheets themselves are in German – just as in class. The editor is only available in German so far.
Calculation triangles – worksheets to print
Two fields inside add up to the number on the edge.
- Choose the number of tasks and the difficulty yourself
- With an answer sheet and, if you like, a QR code to the answers
- At three levels (★ to ★★★) and as group A and B
- As a single worksheet or as a task on a mixed worksheet
Calculation triangles: explained simply
The number outside each side of a calculation triangle is the sum of the two inside numbers next to that side.
How to work it out
- To work outwards, add the two neighbouring inside numbers.
- If an inside number is missing and the matching outside and inside numbers are known, subtract.
An example, step by step
Inside: 3 at the top, 4 at the bottom left and 2 at the bottom right.
- Outside left: 3 + 4 = 7.
- Outside bottom: 4 + 2 = 6.
- Outside right: 3 + 2 = 5. Check each side separately.
Understand other variations
Only the outside numbers are given
Outside left 7, bottom 6, right 5: add 7 + 6 + 5 = 18. Each inside number has been counted twice, so the three inside numbers sum to 18 : 2 = 9. Top: 9 − 6 = 3; bottom left: 9 − 5 = 4; bottom right: 9 − 7 = 2.
Your turn
Outside left is 12; inside top is 5. What is inside bottom left?
Show the answer and method
12 − 5 = 7. Check: 5 + 7 = 12.
Ready-made worksheets: Calculation triangles
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