Reciprocals are important when it comes to dividing fractions, finding perpendicular lines, dealing with inverse proportions, and so much more! In this tutorial you can review the basics about reciprocals.
Multiplying integers is just like performing a bunch of additions of the same integer! Check out this tutorial and see how much multiplying and repeated addition have in common.
The natural numbers are also called the counting numbers. The whole numbers are almost exactly as the natural numbers the same except for one small difference! Watch this tutorial and learn the difference between natural and whole numbers.