VOCABULARY
An EXPRESSION is a mathematical phrase that has NO equal sign.
A VERBAL EXPRESSION is an expression written in words. A NUMERICAL EXPRESSION is an expression with only numbers. An ALGEBRAIC EXPRESSION is an expression that includes numbers, variable, and operations. |
A VARIABLE is a letter that represents a number or value.
TERMS are the elements of an expression that are separated by addition. A COEFFICIENT is a number that is multiplied by the variable. A CONSTANT is a number that stands alone. |
EVALUATING EXPRESSIONS
To evaluate an expression, replace each variable with the given value, then simplify.
**Use Parentheses around the number you are substituting to avoid dropping negative signs, or performing the wrong operation. **
Example #1: Evaluate the expression 4 + a - 2, where a = 3
Step 1: Write out the expression with the variable substituted in --> Step 2: Evaluate, following the order of operations --> Final Answer --> |
4 + a - 2
4 + (3) - 2 7 - 2 5 |
Example #2: Evaluate the expression 6x + 4y, where x = -2 and y = 5
Step 1: Write out the expression with the variable substituted in --> Step 2: Evaluate, following the order of operations --> Final Answer --> |
6x + 4y
6(-2) + 4(5) -12 + 20 8 |
Example #3: Evaluate the expression -a - 3b, where a = -4 and b = 6
Step 1: Write out the expression with the variable substituted in --> Step 2: Evaluate, following the order of operations --> Final Answer --> |
-a - 3b
-(-4) - 3(6) 4 - 18 (KFC)=> 4 + (-18) -14 |
TRANSLATING EXPRESSIONS
Important Words to Know:
Special Words
THAN - FROM - TO mean Switch The Order!!
Examples: a number plus 10 --> x + 10 COMPARE TO: a number more than 10 --> 10 + x a number less 7 --> x - 7 COMPARE TO: a number less than 7 --> 7 - x |
OF means ( ) <-- group what follows the "of" together
Example: the sum of eight and a number --> 8 + x the difference of x and 10 --> x - 10 |