Variable:Is a quantity that can change or vary. Mathematicians use variables (letters) to represent numbers.

Constant:A quantity that does not change.

5w + 18

Expression:Is a mathematical phrase involving constants, variables, and operation symbols.

Evaluate each expression for x=1, 2, and 3.

x x + 5

1

2

3

m m + 10

2

5

11

Evaluate each expression

x 4x + 8

6

10

12

Evaluate each expression

p 12 ÷ p + 2p

2

4

6

Evaluate each expression

c c² + 9 5c + 2 2 • c • 4

5

7

10

Evaluate each expression

x = 3 y = 12 z = 8

4z + 8 – 66x – 9 ÷ 315 + 9x ÷ 37z ÷ 4 + 5xy2 ÷ 3x