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Hello ssendur-- and welcome to English Forums.
Context prevents the original from being misunderstood, and that is a frequent task for context: without it, many utterances are ambiguous.
Yours are OK, too, but one needs punctuation repairs. These are all good in context:
"C++ variables have a property in addition to their value and type known as scope."
"C++ variables have a property known as scope in addition to their value and type."
"C++ variables, in addition to their value and type, have a property known as scope."
or this:
"C++ variables have a property, in addition to their value and type, known as scope."
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