In Norway a widely used concept is that of "tiervenner", "ten friends" (my translation to Finnish is "kymppikaverit"). This simply means numbers (implicitly positive integers) whose sum is ten. There are some resources that name this in Danish, too.

Is a similar term used in other languages? Or, in the absence of such a term, is the concept in use when introducing numbers and simple arithmetic to children?

  • 1
    $\begingroup$ Educators talk about "ten bonds" sometimes. $\endgroup$
    – Sue VanHattum
    Commented Aug 29, 2021 at 18:20
  • $\begingroup$ Are $1.5$ and $8.5$ tiervenner? And what about the triplet $1, 2, 7$? $\endgroup$
    – Dominique
    Commented Jun 6 at 9:19
  • $\begingroup$ Those are good questions. I also like to suggest minus pi and ten plus pi. (The concept is mostly used on the first few grades, so these questions, while fun, are not relevant.) $\endgroup$
    – Tommi
    Commented Jun 6 at 18:23

2 Answers 2


I have seen the phrase "make a ten" in wide circulation. Example:



In German, the word is "Zehnerzerlegung".

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    $\begingroup$ I am a mathematician and German is my mothertongue. I would not know what a "Zehnerzerlegung" is. $\endgroup$
    – Arno
    Commented Aug 29, 2021 at 10:49
  • $\begingroup$ This answer could be improved by a citation or link to a source that shows how the word can be used in the primary school context in German. $\endgroup$ Commented Aug 31, 2021 at 16:45

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