x x x x x
x x x x
-x -x -x
-x -x
Now put them in the same group.
x x x x x
x x x x
-x -x -x
-x -x
How many more x's do you have than minus x's?
Please go back and study the site I posted for you.
Use the "charges" particles model to show that
9+(-5)=4
1 answer