Sylvia simplified the expressions on the Expression Comparison Mat shown at right. Some of her work is shown. Are all of her moves “legal”? Explain.
Go through your list of legal moves and check each move made by Sylvia.
Flipping tiles from the subtraction region to the addition region and changing it from positive to negative is a legal move.
Removing a positive tile from the (
Removing the same amount from both sides is a legal move.
Removing zero pairs is a legal move.