Algebra: Chapter 2-5 and 2-6
Multiplication and Division of Rational Numbers
Today is easy because the rules for multiplication and division are simple. When multiplying 2 numbers AND if the SIGNS are the same, the product is ALWAYS positive. If the signs are different, them the product is ALWAYS negative. This is pretty straightforward. Division follows the same rules as multiplication.
2 rational numbers whose product is 1 are called multiplicative inverses or reciprocals of each other. Just flip the rational expression over and keep the same sign. For example, the reciprocal of `2/3` or `m/n` is `3/2` and `n/m`.
Remember too, to divide rational numbers, sometimes its easier to express them as improper fractions, then convert the 2nd term to its reciprocal and change the `/` to a `*`.
Intro to Algebra: Chapter 1-9
Using Formulas
A formula is an equation that shows a relationship between 2 or more variables. The formula for the area of a rectangle is l⋅w. Given the length and width of an object, you can easily find the area. Be careful, however, and make sure that you are using consistent UNITS in the formula. Do not mix up seconds with minutes or hours or inches with feet or miles. The units must ALWAYS be consistent.
Don’t forget too to add the units to the answer!