Variables and Expressions
2. Larry charges $15 per driveway to clear snow. If 15x represents the amount of money he earned in a week, what does x represent?
A. How big each driveway was
B. The total amount of money he earned
C. The number of driveways he cleared
D. The amount he charges for each driveway
C. The number of driveways he cleared
8. Mrs. Jenison ordered 7 small notepads and 6 large notepads for each of 3 teachers. Which expression represents the total number of notepads Mrs. Jenison ordered?
A. 7x6x3
B. (7+3)x6
C. 7+(6x3)
D. (7+6)x3
D. (7+6)x3
5. Write an expression to show how to find the number of candy bars in b boxes.
Boxes- 3 4 5 6
Candy Bars. 24 32 40 48
8
Not on practice sheet
What is a variable?
A letter or symbol that you represent the unknown value that can vary or change.
1. Which expression can be used to represent the phrase "three more than a number"?
A. F+3
B. 3+F
C. F-3
D. 26-3
B. 3+F
9. Which expression has a value of 34?
A. 4x(5+6)
B. (4x5)+6
C. 4+(5x6)
D. (4+5)x6
C. 4+(5x6)
4+30
34
6. The cost for (p) pencil cases for students is 8p+6 dollars. What is the cost of 4 pencil cases?
8(4)+6
32+6
38
Not on practice sheet
What is an algebraic expression?
A mathematical expression using a variable.
4. Write a sentence about a real-life situation that matches the expression 5h.
Johnny's family of 5 each ate (h) amount of hotdogs for dinner.
11. Evaluate the expression:
50x2-6/3
A. 7
B. 98
C. 13
D. 24
50x2-6/3
100-6/3
100-2
B-98
7. If Tony writes an average of 38 pages a week for 8 weeks, he will have written 38x8 pages. Which of the following is equal to 38x8?
A. (30x8)-(8x8)
B. (30+8)x(8x8)
C. (30+8)+(8+8)
D. (30x8)+(8x8)
D. (30x8)+(8x8)
In the Order of Operations, what step comes first?
A. Addition
B. Parenthesis
C. Multiplication
D. Division
B. Parenthesis
Not on practice sheet
What part of the expression is a variable?
2xa=10
a
12. Evaluate the expression:
35-3(5+2)
35-3(5+2)
35-3x7
35-21
14
10. Lori was solving this problem on the board
7+(4x7)-8/6
Which operation should Lori do first?
A. Add
B. Subtract
C. Multiply
D. Divide
C. Multiply because it is in parenthesis.
What is sum? What is a difference?
A sum is the answer to an addition problem. A difference is the answer to a subtraction problem.
3. Write a sentence about a real-life situation that matches the expression s-3.
There are (s) slices of pizza, Amy ate 3 slices of pizza.
13. Evaluate the expression:
(50-(4x10)+12
(50-(4x10)+12
(50-40)+12
10+12
22
14. Mrs. Story wrote the two expressions below on the board.
3x7+6 and 3x(7+6)
David says the two expressions have different answers. Tanya says the two expressions will have the same answers.
Evaluate both expressions. Then tell who was correct and who was incorrect about the answers to the expressions, and explain the error made by the student who was incorrect.
3x7+6 3x(7+6)
21+6 3x13
27 39
David is correct since the expressions are different. Tanya was incorrect because the answers to the expressions are not the same, she did not follow the correct order of operations when solving the two expressions.
In the Order of Operations when multiplying, dividing, adding and subtracting, do you go (right to left) or (left to right).
Left to right.