Evaluating Algebraic Expressions Intro to Algebra Numerical Expression

Evaluating Algebraic Expressions Intro to Algebra

Numerical Expression A numerical expression represents one value and can contain one or more numbers and operations. 4 + 5 is a numerical expression. It represents the value 9.

Example Which numerical expressions represent a value of 21? a) 9 + 24 b) 4 + 7 + 14 c) 9 + 4 + 10 d) 7 x 3 e) 5 + 2 x 2 - 1 f) 160 ÷ 8

What if they are not numbers? 7+x 4 y + 3 8–y÷ 2

Variables A variable is a symbol that can represent different values. We can substitute numbers in for variables to give the expression a value.

Algebraic Expression An algebraic expression contains variables, numbers and operations. The value of an algebraic expression can change.

Parts of an Algebraic Expression • Terms – A term can be a constant, a variable, or a number with a variable. Terms are separated by either a + or a – sign. • Coefficient – In a single term containing a number and a variable, the number in front of the variable is called the coefficient.

A Number next to a Variable What does it mean when a number is written next to a variable? 4 x it means to multiply. 4 x means 4 times x.

Examples •

Evaluating more expressions 1. p + 11 – q (when q = 16, p = 32) 2. 1 ÷ x · y (when y = 4, x = 1) 3. 14 + b · c (when b = 2, c = 3)