Chapter 5.1 -
Evaluating Variable Expressions
Before we begin, let's define a few words.
Variable - quantity that can change, or vary, taking on different values
(usually represented with a letter)
Expression - one or a group of mathematical symbols representing a number or quantity
(example - 3x + 4)
Equation - mathematical statement containing an eqauls sign to show the two expression are equal (example 6 + 4 = 10 or 3 + x = 5)
Term - one part of an expression
(example - for the expression 2a + b, 2a and b are both terms
Coefficient - a number which mulitplies a variable
(example - 3 is the coefficient of 3x, or 5 is the coefficient of 5y)
Constant - a quantity having a fixed value that does not change or vary
(example - in the expression 3x + 4, 4 is the constant)
Use the image below to review the vocab words.
We will have a quiz over these words very soon.
Ch 5.1 Vocab
Writing expressions can be tricky... here are some hints to help you.
Math Words & What They Mean...
Quotient - the answer to a division problem - the quotient of x and 3 would be x/3
Divided by - division - x divided by 4 would be x/4
Product - the answer to a multiplication problem - the product of n and 3 would be 3n (the number is always before the variable)
Times - multplication - 3 times m would be 3m
Multiply by - multiplicaton - mutiply 4 by x would be 4x
More than - addition - 6 more than r would be r+6
Total of - addition - the total of 5 and m would be 5+m
Sum - answer to an addition problem - the sum of x and 6 would be x+6
Difference - the answer to a subtraction problem - the difference of x and a number would be x-6 (same order as words)
Minus - subtraction - 5 minus x would be 5-x (same order as words)
Less than - subtraction - 6 less than p would be p-6 (backwards from words)
Fewer than - subtraction - x fewer than 10 would be 10-x (backwards from words)