# Scientists Say: Algebra

## This is a kind of math in which letters can sub in for numbers

**Algebra **(noun, “AL-jeh-brah”)

This is a kind of math in which letters and symbols take the place of numbers. By substituting letters for numbers, algebra allows us to take specific equations and make them apply to more situations.

For example, in arithmetic (which is another kind of math), we could say that 1 + 2 = 3. In algebra, we could replace each number with a letter, such as x + y = z. Those letters could represent any number, as long as the results are still true. So x + y = z could be 1 + 2 = 3. But it could also be 7 + 5 = 12. Or 1,000 + 2,431 = 3,431. As long as x + y = z, the letters could represent any numbers at all.

This sounds like math class, doesn’t it? But algebra isn’t just for the classroom. People use it every day. Algebra can be especially helpful in figuring out unknown amounts. If you want to go to a friend’s house and need to know if it will take longer to walk or to bike, you’ll need to do algebra to find out. Comparing prices when you shop? You’ll use algebra. If you want to put in a floor, sew a quilt, knit a scarf or paint a wall, you will use algebra to find out how much material you need.

The word “algebra” comes from the Arabic word “al-jabr.” It can mean “reduction” or “bringing together broken things.” Much of what we know about algebra comes from Greek and Persian mathematicians working more than 1,200 years ago.

#### In a sentence

Scientists are using algebra to help design tiny origami robots that can squeeze and bend into tiny spaces.