OK, we've had our introductions and we're almost finished week one. But at this point you may be wondering: what exactly is algebra?

ancient algebra textAlgebra is a branch of mathematics that deals with symbols. It is a very old kind of math: ancient Arabic and Persian peoples worked out the ideas over a thousand years ago. To the left, you can see a page from a Persian book about algebra written in 820 AD.

In algebra, letters are used to represent numbers that are not known to us at the start of the problem. The letters are the "mystery numbers" in the equation. In simpler terms, a letter is used to indicate the number that you need to find in a calculation. In elementary or public school, you probably saw question marks ( ? ) used the same way, like this:

4 + 3 = ?
Or maybe like this:
7 + ? = 9
But in the higher grades, we use a letter (often the letter "x") instead, and we call this algebra. Are you ready to have a look at a few examples? See if you can figure out what "x" should be:

Question: 4 + x = 10

Answer: x = 6 (because 4 + 6 = 10)

Here's another one:

Question: x - 5 = 8

Answer: x = 13 (...because 13 - 5 = 8)

We can use a letter with multiplication and division problems, too:
7 times y = 21
In this case,
y = 3, because 7 x 3 = 21
And, for division:
32 ÷ x = 4
x = 8 (...because 32 ÷ 8 = 4)
See? That's not too hard, is it? If you'd like to try finding x for a few questions, try the "first practice" (it's the next activity on this list).
Last modified: Tuesday, 26 July 2011, 5:04 PM