Hi! This is Rob. Welcome to Math Antics.

In this lesson, we're going to learn some really important things

about a whole branch of math called Algebra.

The first thing you need to know is that Algebra is a lot like arithmetic.

It follows all the rules of arithmetic

and it uses the same four main operations that arithmetic is built on:

addition, subtraction, multiplication and division.

But Algebra introduces a new element...

the element of the unknown.

When you were learning arithmetic,

the only thing that was ever unknown was the answer to the problem.

For example, you might have the problem 1 + 2 = what?

The answer isn't known until you go ahead and do the arithmetic.

Now the important thing about Algebra is that when we don't know what a number is yet,

we use a symbol in its place.

that symbol is usually just any letter of the alphabet.

A really popular letter to choose is the letter 'x'.

So in arithmetic, we would just leave the problem like this: 1 + 2 = "blank"

and we'd write in the answer when we did the addition.

But in Algebra, we'd write it like this: 1 + 2 = x

The 'x' is a place holder that stands for the number that we don't know yet.

What we have here is a very basic algebraic equation.

An equation is just a mathematical statement that two things are equal.

An equation says, "the things on this side of the equal sign

have the same value as the things on the other side of the equal sign."

In this case, our equation is telling us that the known values on this side (1+2)

are equal to what's on the other side,

which happens to be the unknown value that we are calling 'x'.

One of the main goals in Algebra

is to figure out what the unknown values in equations are.

And when you do that, it's called "solving the equations".

In this equation, it's pretty easy to see that the unknown value is just 3.

All you have to do is actually add the 1 and 2 together on this side of the equation

and it turns into 3 = x, which is the same as x = 3.

So now we know what 'x' is! It's just 3.

That almost seems too easy, doesn’t it?

And that's why in Algebra, you are usually given an equation in a more complicated form

like this: x - 2 = 1.

This is exactly the same equation as 1 + 2 = x,