Which addition sentence represents the model -5+1?

The addition sentence that accurately represents the model (-5 + 1) simplifies to (-4). This is achieved by interpreting the operation as starting at (-5) on the number line and moving one unit to the right, which effectively increases the value by 1. In mathematical terms, adding a positive number (in this case, 1) to a negative number results in a number that is less negative, moving us closer to zero.

Since (-5 + 1) equals (-4), the corresponding addition sentence is clearly illustrated as (-5 + 1 = -4). This direct representation allows for a straightforward understanding of how addition involving negative numbers operates within the number system. The correct answer encompasses these foundational principles of arithmetic with negative integers.