15-1 Solving Addition and Subtraction Equations
We learned that an equation is a formula that shows two expressions that have the same value. Next we learned about the Addition and Subtraction Properties of Equality which provide that you can add or subtract the same value to both sides of an equation and the equation will remain the same. Then we learned that addition and subtraction have an inverse relationship because they have the opposite effect which is that they undo each other.
15-2 Solving Multiplication and Division Equations
We learned that the Commutative Property for Multiplication stating that a x b is equal to b x a is always true, regardless of the values substituted for the variables. Then we learned that the Multiplication and Division Properties of Equality provide that you can multiply or divide both sides of an equation by the same nonzero number without changing the value of the equation. Next we learned that multiplication and division have an inverse relationship because they have the opposite effect.