Which mathematical property is demonstrated? 7+9+3=7+3+9

The property that allows 7 + 9 + 3 = 7 + 3 + 9 is called the Commutative Property of Addition and Multiplication. This means that as long as the sign is either a multiplication symbol or an addition symbol, we can move (or "commute") the values wherever we want and the expression will still equal the same amount.
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