Balancing the seesaw
Think of an equation as a balanced seesaw: whatever you do to one side you must do to the other, or it tips. To find x in x + 3 = 7, you lift 3 off both sides and the seesaw still balances, leaving x = 4.
Keep both sides equal
An equation is a balance. Whatever you do to one side you must do to the other. To solve for x, undo operations in reverse order using their inverses.
2x + 3 = 11 2x = 8 (subtract 3 from both sides) x = 4 (divide both sides by 2)