Trying to find the surface area of a sphere? Already know the radius? Then plug that value into the formula for the surface area of a sphere and solve to get the answer! This tutorial shows you how!

Is an irrational number just a way to describe a number that's lost its mind? Not really. :) An irrational number is simply a number that cannot be written as a fraction. Check out the definition, learn an important property of these special numbers, and take a look at some examples of irrational numbers.

You can't do algebra without working with variables, but variables can be confusing. If you've ever wondered what variables are, then this tutorial is for you!

Check out this tutorial where you'll see exactly what order you need to follow when you simplify expressions. You'll also see what happens when you don't follow these rules, and you'll find out why order of operations is so important!

Want to know how the find the lateral and surface areas of a cylinder? Then this tutorial was made for you! You'll see how to apply each formula to the given information to find the lateral area and surface area. Check it out!