I am so sorry, I know I have asked that question before but I still do not see the difference between those two sentences.

In my book it says:
"Nous avons besoin des nombres pour le commerce."
and then it says:
"Nous avons besoin de nombres pour désigner les dates, les heures...."
Why is it once "nous avons besoin DES nombres pour..." and then "nous avons besoin DE nombres pour...."??
When I put these sentences into the translater site, it gives me exactly the same as the book: once "des" and once "de".
I just can't see the differeence.
Thank you!

This is an excellent question, actually! It is ordinarily "avoir besoin de/d'" except:

It's always "de" but with :
de le = du
de les = des
de un = d'un
de une = d'une

For example:
1. I need (I have need of) some overcoats. = J'ai besoin de manteaux.
2. I need (I have need of) THE overcoat I bought yesterday. = J'ai besoin DU manteau que j'ai acheté hier.
3. I need (I have need of) THE overcoats... = J'ai besoin des manteaux.
4. I need (I have need of) an overcoat. = J'ai besoin D'UN manteau.

Your example above would be the difference between:
1. I need THE names...
2. We need SOME names...

(picky, picky!)

Hmmmmm. I wouldn't use a translation site! Did you try both ways = entering the French for the English and then the English for the French? Try that and see what you get? You really can not depend upon translation sites anyway!

Sra (aka Mme)

In other words one (commerce) is more generic and the other(dates, times) is more specified?

No, I didn't try the translation site both ways but I'll do it now just to see what it comes up with. I know that these sites are not exactly great because they usually translate phrases word for word and often fail to recognize "sayings", etc.
Thank you again for being so patient with me!

I just cross-referenced these sentences.

When I put the French version in I got the following English translation:
1) we need THE numbers for the trade
2) we need numbers for the dates

One more word on "translation sites".
I once put in the sentence: "I have to get dressed now" and the answer was:
"je dois obtenir habillé maintenant"
I knew that this was incorrect(because it translated it word for word) and it was not until I rephrased it to:
"I have to dress myself now" that I received the correct answer "je dois m'habiller maintenant."
Thank you so much again for all your help!!!

See the difference then between "SOME" and "THE?"

Sra (aka Mme)

Yes, i do. Thank you so very, very much!

No problem! I understand that the use of "des" and "de" in French can be confusing. Let me explain it to you.

In French, "des" is a partitive article used to indicate an indefinite quantity or some amount of something. On the other hand, "de" is a preposition used to express possession, origin, or the purpose or reason for something.

In the sentence "Nous avons besoin des nombres pour le commerce," the partitive article "des" is used before "nombres." The word "des" indicates an indefinite quantity, meaning "some" or "a few" numbers. So the sentence translates to "We need some numbers for trade."

In the second sentence, "Nous avons besoin de nombres pour désigner les dates, les heures...," the preposition "de" is used before "nombres." In this context, "de" expresses the purpose or reason for something. So the sentence translates to "We need numbers to designate dates, hours..."

When you enter these sentences into a translation website, it might give you the same result because both "des" and "de" can be translated to "of" or be omitted in English. However, the difference in usage is important in French because it conveys a different nuance in meaning.

I hope this explanation clarifies the difference between "des" and "de" for you! Let me know if you have any further questions.