Which property allows for changing the grouping of numbers without affecting the value?

The property that allows for changing the grouping of numbers without affecting the value is the Associative Property. This property indicates that when performing addition or multiplication, the way in which the numbers are grouped does not change their sum or product. For example, in addition, (a + b) + c is the same as a + (b + c). This demonstrates that no matter how the numbers are grouped, the overall result remains unchanged.

The Associative Property is fundamental in simplifying mathematical expressions and solving equations, as it provides flexibility in computation. It emphasizes that the focus should be on the numbers themselves rather than their arrangement or grouping. This concept applies to both addition and multiplication, but not to subtraction or division, which do not maintain the same results when the grouping changes.