PSSA PREP
PSSA 4.8 Expressions and Open Sentences
Variable -- a letter used to represent a number
Term – a number, variable, or the product / quotient of a number and variable
Variable Expression – is made up of more than one term.
Order of Operations – PEMDAS
1.) Simplify Parentheses or Grouping Symbols
2.) Simplify any terms with Exponents
3.) Multiply and Divide in order from left to right.
4.) Add and Subtract in order from left to right.
Like Terms -- terms with exactly the same variables raised to the same powers. Their
coefficients may be different.
Combining Like Terms – or simplifying variable expressions. If you have like terms,
they may be combined be adding / subtracting the coefficients of the terms. The
variable part stays the same!
EX: Simplify.
a.) 4a 2b + 3ab 2 − 2a 2b + 7ab 2
EX: Evaluate:
x 2 + 2 x − 3xy + 2 xy 2
for x = 2 and y = –3
b.) 3x + 3x 2 − 4 x + 5 y 2
EX: Write a variable expression or equation for the following:
A.) The product of 2 and a number plus 7.
B.) 5 less than three times a number
C.) The sum of two consecutive integers.
D.) What number doubled gives a result of 18?
E.) Three times one more than a number is at least 26.
Homework: PSSA Workbook p. 217 #1 – 4, 7, 8, 10, 11