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.