Exploring Variables and Evaluating Expressions in Equations

1. Sarah has x apples. If she buys 5 more apples, how many apples does she have now? Write an equation to represent this situation.

• x + 5

• x - 5

• x + 10

• 5 - x

2. A rectangle has a length of 3 meters and a width of w meters. Write an expression for the perimeter of the rectangle and evaluate it when w = 4.

• 16 meters

• 12 meters

• 14 meters

• 10 meters

3. Tom is saving money. He has y dollars and saves 10 more each week. Write an equation to show how much money he will have after 3 weeks.

• y + 30

• y + 10

• y + 20

• y + 40

4. A car travels at a speed of s miles per hour. How far will it travel in 4 hours? Write an expression for the distance and evaluate it when s = 60.

• 300 miles

• 240 miles

• 180 miles

• 120 miles

5. The total cost C of buying x notebooks at $2 each can be represented by the equation C = 2x. How much will it cost to buy 10 notebooks?

• 30

• 15

• 20

• 25

6. A book has p pages. If you read 15 pages each day, write an equation to find out how many days it will take to finish the book when p = 75.

• 3

• 10

• 7

• 5

7. Lisa has z stickers. If she gives away 8 stickers, how many does she have left? Write an equation to represent this situation.

• z + 8

• z - 5

• 8 - z

• z - 8

8. A box contains b balls. If 12 balls are added to the box, write an expression for the total number of balls and evaluate it when b = 20.

• 36

• 24

• 28

• 32

9. The temperature t in degrees Celsius can be converted to Fahrenheit using the equation F = (9/5)t + 32. What is the temperature in Fahrenheit when t = 25?

• 72

• 80

• 77

• 90

10. A farmer has f fields. If he plants 3 crops in each field, write an expression for the total number of crops and evaluate it when f = 5.

• 15

• 12

• 10

• 20