Unit 2 Study Guide

What is a variable?

• A letter in math that stands for other letters.

• A symbol that means change.

• A letter in math that stands for an unknown number.

• A symbol that means to multiply.

What is an expression?

• Combination of numbers, operations, and variables.

• An equation.

• When you replace a variable with a number.

• I don't know, Mr. Soto.

What is the word we use to help us remember the correct order of operations?

• Substitution

• Variable

• Parenthesis

• PEMDAS

Evaluate the expression:

5n + 10

Use n= 3

• 25
• 63
• 530

Evaluate the expression:

y + 18 ÷ 3

Use y= 9

• 9

• 15

• 3

Evaluate when a = 15:
2(a - 5) + 2

• 22
• 27
• 14
• 7

Evaluate the expression:

2x + 3 + x²

Use x = 4

• 17
• 27
• 19
• 25

Evaluate:

2a + 4b 
if a = 10  and b = 6

• 20
• 24
• 44
• 4

Evaluate the expression:

2x + 5(y - 1)

Use x=8 and y=5

• 20
• 31
• 36
• -4

How many terms are in the following expression?
8n + 2 - 7x

• 1
• 2
• 3
• 4