Notice that the scales above are balanced because each pan has a five on it. Now look at the next figure. This scale is also balanced, because the total on each side is 5. It is important to understand that we want to keep the pans balanced. But if we added 2 to both pans, the scales would remain balanced since both sides would yield a sum of 7.
Students can think of the center bar as the equals sign.
A key rule for working with equations is that you can add the same number to each side, subtract the same number from each side, and multiply or divide each side by the same number and the sides will stay equal. You must, however, do exactly the same operation to each side, or the equation will become unbalanced. All Rights Reserved.