The part before the repetend

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Question from Puerto, a teacher:

Hello,
I teach mathematics in a bilingual programme using English. I have learned that the group of digits that repeat in a repeating decimal is called repetend but i need to know how are called the previous ones when the decimal is a delayed-repeating one. I mean, in 0.34555555 5 is the repetend, the period is one and...how are called 34?
Thanks in advance.

We have two responses for you

Hi there.

I hadn't actually heard of the term "repetend", but that sounds right. I would call the digits that come before the repetend the "prefix". Perhaps you can find a more "official" word for it, but I think that "prefix" has a clear meaning.

Cheers,
Stephen La Rocque.

Puerto,

Repetend is the correct word for the repeating part. You can find some information and terminology around repeating decimals under R in Earliest Known Uses of Some of the Words of Mathematics. I couldn't however find any word for the part of the repeating decimal that precedes the repetend. I like Stephen's suggestion of prefix.

I am curious. Is there a word for this in Spanish?

Penny

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