Explain the Algebraic Expressions and Equations?

Writing a math problem algebraically means that you are using numbers and variables to represent relationships.

"Three inches taller than Danielle" can be represented in the algebraic expression 3+d.

"Ernesto is three inches taller than Danielle" could be represented in the algebraic equation E = 3+d.

What does an equation have that an expression doesn't?

An equation has an equal sign ("=").

The variables used in the instances are "e" for Ernesto's height and "d" for Danielle's height. Remember that the first letters of the people's names were used as the variables. In general, while you're deciding that letter to use for your variable, the first letter of the object being measured is an excellent choice.

So, a variable is a letter that represents a number that is unknown, or that changes (varies) depending on the situation. For example, for the above equation, e = 3+d; depending on how old Danielle is, her height will change.