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Basic Algebra/Introduction to Basic Algebra Ideas/Variables and Expressions
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Vocabulary
Variable
Term
Operation
Expression
Evaluate
Substitute
Lesson
A variable is a letter or symbol that takes place of a number in Algebra. Common symbols used are , , , and . The letters x and y are commonly used, but remember that any other symbols would work just as well.
Variables are used in algebra as placeholders for unknown numbers. If you see "3 + x", don't panic! All this means is that we are adding a number who's value we don't yet know.
Some examples of variables in use:
-- three times of .
-- five minus
or -- 2 divided by
A term is a number or a variable or a cluster of numbers and variables multiplied and or divided separated by addition and subtraction.
Examples of terms:
The terms are 3 and 5.
The term is , 6 over is one term, because the operation is division.
The terms are 6 and 5, 6 and 5 are separate terms because they are separated by a addition or subtraction.
An operation is a thing you do to numbers, like add, subtract, multiply, or divide. You use signs like +, –, *, or / for operations.
An expression is one or more terms, with operations between all terms.
Examples of expressions:
To evaluate an expression, you do the operations to the terms of an expression.
Examples of evaluating expressions:
evaluates to 7.
evaluates to 6.
evaluates to 17.
To evaluate an expression with variables, you substitute (put a thing in the place of an other thing) numbers for the variables.
Examples of substituting: (Substitute 3 for x in these examples.)
is .
is .
is .
Example Problems
Evaluate the following expressions
When Substitute 2 for . Evaluate to get the answer.
When and Substitute 9 for and substitute 4 for . Evaluate to get the answer.
Practice Games
Evaluating expressions
Advanced Expression Evaluator
Practice Problems
remember order of operations
{Evaluate each expression if = 1, = 2, = 3, and = 5.}
{
|type="{}"}
{ 10_2 }
{
|type="{}"}
{ 27_2 }
{
|type="{}"}
{ 1_2 }
{
|type="{}"}
{ 0_2 }
{
|type="{}"}
{ 1_2 }
{
|type="{}"}
{ 12_2 }
{
|type="{}"}
{ 8_2 }
{
|type="{}"}
{ 25_2 }
{Evaluate each expression if = 4, = 2, and = 3.}
{
|type="{}"}
{ 6_2 }
{
|type="{}"}
{ 6_2 }
{
|type="{}"}
{ 12_2 }
{
|type="{}"}
{ 9_2 }
{
|type="{}"}
{ 11_2 }
{
|type="{}"}
{ 2_2 }
{
|type="{}"}
{ 6_2 }
{
|type="{}"}
{ 2_2 }
{More harder questions:
Evaluate each expression if = 5, = 8, and = 9.}
{
|type="{}" coef="2"}
{ 56_2 }
{
|type="{}" coef="2"}
{ 3_2 }
{
|type="{}" coef="2"}
{ 0_2 }
{
|type="{}" coef="2"}
{ 11_2 }
{
|type="{}" coef="2"}
{ -4_2 }
Basic Algebra Variables and Expressions Order of Operations Working With Negative Numbers