Algebra Lesson 1 : Algebra Lesson 1 Variables & Expressions
Algebra : Algebra Algebra is a language of symbols.
The symbols can include numbers, letters, characters, and operation signs.
Variables : Variables Variables are symbols used in algebra to represent a number.
For example:
If we are looking at finding the cost of gift wrapping and the way we find it is by adding the Length and the Width and multiplying by 5 cents we can represent this by (L + W) X 5
In this example the L & W are variables
The L represents the Length, and the W represents the Width
Expressions : Expressions An algebraic expression is a combination of variables, numbers, and at least one operation.
For example:
(L + W) X 5
Evaluating an Expression : Evaluating an Expression Variables in an expression can be replaced with any number.
When the variables have been replaced you can evaluate (find the value of) the expression.
For example:
(L + W) X 5; Let L = 10 and W = 4
(10 + 4) X 5
14 X 5
70
Bonus Slide (Representing Multiplication) : Bonus Slide (Representing Multiplication) Multiplication can be represented in algebra in several different ways
It can be represented in the traditional way
3 X m or 3 * m
It can be represented by a dot
3 • m
It can be represented by parentheses
3(m)
It can be represented by a number and a variable or two variables right next to one another
3m
mn (which means m X n)
Example : Example Evaluate 3m + 2 • 4 if m = 12
3 X 12 + 2 • 4
36 + 2 • 4
36 + 8
44