Question

How you could use a number line to show that -4 plus 3 and 3 plus (-4) have the same value. Which property of addition states that these sums are equivalent

Answer 1

Using a number line to show what -4 + 3 equals:

Start at the -4.  Move three spaces to the right (+3).  You land on -1.

Using a number line to show what 3 + (-4) equals:

Start at the 3.  Move four spaces to the left (-4).  You land on -1.

The commutative property of addition states that a + b = b + a.