=

This operation always produces an expression which describes a relationship between its left and right side. Unlike the == operator which determines whether one value equals another, this operation is like a mathematical relationship. A good example of this kind of expression is the standard equation for a line, y = mx + b. Assuming that m and b are constant values, the equation creates a relationship between x an y. Also, the equation can be manipulated to produce equivalent equations like y - b = mx.

Similarly, expressions which contain an equals operation can also be manipulated in the same way on the calculator. Assume that 3 is added to the expression "left=right". This would produce the equation "left+3=right+3". The operation is applied to both sides of the equation to balance it. This works for addition and all other operations which take expressions.

Also, assume there are two equations being added together, "A=B" and "C=D". This will result in "A+B=C+D". Again, this works with operations like add and all others which operate on expressions.