In App, why does scanning a bar code work, when typing it does not? UPC/EAN

I'm testing with
ISBN 978-1-5317-0237-3
UPC 8 41887 03406 7

In the Library Thing app, if I scan the UPC bar code, the DVD comes right up. If I type the above numbers instead, it does not.

If I search by title, there are so many similar DVD's it's hard to find the right one.

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Why are these two methods (scan vs. type) different?
Is there a way to do a deeper search via the app?

When you type it in, do you include the dashes?

I did not include dashes.
But that did not seem to matter.
Mostly I speak the number, which adds spaces:
8 4 1 8 8 7 0 3 4 0 6 7

How should I format UPC and ISBN numbers for Library Thing? Is there a way to get it to normalize the numbers (e.g. remove spaces and remove dashes, just use them as hints)?

No dashes and no spaces.

I'll report that a bug. Would take seconds for LT's maintainer to trim whitespace. ( string.trim() )

I believe trim only removes white space from the beginning and end of the string, not the middle.