-8 -7
-6
-5
-4
+
0 1 2
-3
-2
-8
-7
-6
-5
-4
-3
-2
-1
0 1 2
-8 7
-6 -5
-4
-3
.-2
-1
0 1
2
-8
+
2
-7
-6
-3
-2
-1
0
1
Compare and contrast the four number lines. Decide which number line doesn't belong. Justify your reasoning.

  take your pick. Each has its own reason.

Step-by-step explanation:

As with a lot of "doesn't belong" problems, the one that is different depends on your criteria. In the attached figure, each one "doesn't belong" for a different reason. Those reasons are listed below each number line.

__

I might choose the lower left: "addition, not subtraction", as it is the only one with arrows in the same direction. That makes its difference from the others more obvious, perhaps.