1. Writing Algebraic Expressions
21st Century Lessons
Writing Algebraic Expressions
Lesson 2

2. Warm Up
OBJECTIVE: SWBAT write algebraic expressions using grouping symbols and the phrase less than. As well as write written expressions from algebraic expressions.
Language Objective: SWBAT speak with a partner about translations between algebra and English.
Sally made 20 more shots than Kevin, k. Write an algebraic expression to represent how many shots Sally made.
k+20
20+k or
2) Damon bought a bin of 68 sour candies. He ate c candies. Write an algebraic expression to represent how many candies Damon has left.
68 – c
(Time on this slide - 5 min) Time passed 5 min
In-Class Notes
Read the slide to the class for them to answer or have them read silently.
Clicking will reveal the answers.
Preparation Notes
The goal of this slide is to review what students have learned in the previous lesson, or their knowledge of writing algebraic expressions.
3) What were the key words that helped you write the algebraic expressions for the problems above?
Agenda

3. Agenda: 1) Warm Up Individual 2) Launch Marvin’s Math- Whole Class
OBJECTIVE: SWBAT write algebraic expressions using grouping symbols and the phrase less than. As well as write written expressions from algebraic expressions.
Language Objective: SWBT to translate the meaning ‘sum of’ and ‘difference of’ into algebraic expressions.
1) Warm Up
Individual
2) Launch
Marvin’s Math- Whole Class
3) Explore 1
Marvin’s Math Part 1- Whole Class
4) Explore 2
Marvin’s Math Part 2- Whole Class
5) Practice
Class Work- Partners
(Time on this slide - 1 min) Time passed 6 min
In-Class Notes
Quickly go over agenda. Great chance to review objective and language objective with students.
Preparation Notes
6) Assessment
Exit Slip- Individual
Agenda

4. Marvin’s Math Launch- Marvin’s Math Pick a number, add two,
multiply by five.
Let’s get a few volunteers.
What number did you pick? What was your result?
What did you do first?
What did you do second?
(Time on this slide – 5 min) Time passed 11 min
In-Class Notes
Students should do the work in their notebook.
Read the slide as it appears.
Stress the fact that each students performed addition before multiplication.
Everyone performs the steps using 18. The explanation is on the next slide.
Preparation Notes
The goal of this slide is to scaffold how to write algebraic expressions containing grouping symbols. Read the slide as it appears. Ask one student for their result. Advance the slide asking the questions as they appear (what did you do first, what did you do second?). Leave the questions up as you ask for more volunteers. (If possible, recording student’s responses may be helpful for students to see that the addition is performed first.) Be sure to stress the fact that each student performed addition first then multiplication. When the prompt comes up for all students to perform the steps with the number 18, explain it is so that we as a class can work together on the next part. The explanation is on the next slide.
Now everyone, let’s use the same number 18.
Agenda
Agenda 4

5. Marvin’s Math Explore- Marvin’s Math: Part 1 Pick a number , add two
, multiply by five.
What was everyone’s result using 18?
Great! Everyone’s response is 100. This is my numerical expression using the number 18.
(Time on this slide – 4 min) Time passed 15 min
In-Class Notes
Read the slide as it appears.
Give students about 2 minutes for their turn and talk.
The discussion leads into the next slide.
May need to review what a numerical expression is.
Preparation Notes
The goal of this slide is get students thinking about what to do in writing expressions when you have to add first. Read the slide as it appears. Be sure to explain why the answer in 100 in case some students obtain an incorect answer. Give students about 2 minutes for their turn and talk. The discussion is on the next slide.
Turn and talk: Is Marvin’s expression correct?
Explain your reasoning.
Agenda
Agenda 5

6. Explore- Marvin’s Math: Part 1
Turn and talk: Is Marvin’s expression correct?
No! What do we need to do in order to make this expression equal 100?
Hint
Numerical
Expression.
(Time on this slide – 3 min) Time passed 18 min
In-Class Notes
Read the slide as it appears.
Read the question in the slide.
May need to use the hint depending how students answer the questions.
Show the correct expression.
Preparation Notes
As students finish their discussion on whether or not Marvin’s expression is correct, ask for volunteers to share their thoughts. Read the slide as it appears. Review that Marvin is incorrect due to the fact that he didn’t follow the order of operations. A hint is given if students need more prompting on what can be used when trying to add first. Depending how your students answer the question, you may not need the hint. Show the correct expression for students to copy in their notebooks. Be sure to emphasize the purpose and importance of the grouping symbols. This is a great opportunity for the students to visually see the difference of using grouping symbols and how they can change the value of the expression.
Agenda

7. Explore- Marvin’s Math: Part 1
Turn and talk: Is Marvin’s expression correct?
No! What do we need to do in order to make this expression equal 100?
Since we have to add first, what can we use to show that we want to perform addition FIRST?
In-Class Notes
This is a hidden slide for the hint.
Numerical
Expression
Agenda

8. Explore- Marvin’s Math: Part 1
Pick a number, add two, multiply by five.
Numerical
Expression
If 10 is picked
If 1 is picked
Our goal is to write this as an
Algebraic Expression.
(Time on this slide - 4 min) Time passed 22 min
In-Class Notes
Read slide as it appears.
This will show the process for thinking about how to write an algebraic expression.
Once the Algebraic Expression appears in the slide, prompt students what can we use to represent any number.
Preparation Notes
The goal of this slide is to show the process of writing Marvin's Math into an algebraic expression. Advancing the slide will show the process of choosing different numbers to help visually see that only number changes. Once the goal appears, prompt students by asking, “What can replace all these different numbers with?” “What in math represents an “unknown”?”
Agenda

9. Explore- Marvin’s Math: Part 1 Algebraic Expression
Our next goal is to write this as an
Written Expression.
Let’s break it down into 2 parts.
How do you think we should write as a written expression?
The word sum prompts you to add first.
The sum of a number and two.
Next we combine the two parts.
The sum of a number and two, times five.
(Time on this slide - 4 min) Time passed 26 min
In-Class Notes
Read the slide as it appears.
May have to prompt students to think of ways to translate (x + 2).
Continue with the slide.
Preparation Notes
Read the slide as it appears. This is designed to scaffold how to write more challenging algebraic expressions. When asked to write a written expression, students may want to actually use the wording “parentheses”. Also, may need to review the definition of the word. Should students come up with this, this is an opportune time to explain that are other ways to express the word “parentheses”.
Go through the slide as it appears. To help with writing (x + 2), take some suggestions: Ask students how they would write it. Record answers on side board if possible. From the previous lessons, they will come up with several answers. If students do not use the word, “sum of”, ask, “How can we write this using the word, sum?” then continue with the slide.
Note: Throughout this lesson, students may come up with other ways to write the expression than what is presented in the lesson. It is encourage to not dismiss student’s thinking and encourage more ways and have discussions around them.
Agenda

10. OBJECTIVE ALERT Practice problems Explore- Marvin’s Math: Part 1
Algebraic Expression
Written Expression
The sum of a number and two, times five.
Practice problems
Ex. 1 Write a for
written expression
The sum of a number and four, divided by ten
(Time on this slide – 5 min) Time passed 31 min
In-Class Notes
Read slide as it appears.
Keep in mind may have different responses than the ones provided in the slide. Discussion should be had for all responses given.
Preparation Notes
The beginning of the slide shows the algebraic expression and the written expression side by side. The goal of this slide is to have students practice as a whole class. Keep in mind there are a couple of ways to translate the expressions, which if a brought up by students should be discussed. The translation provided is not the only one to be used or discussed, but most likely will be the common one used by students.
Example 2 provided two different examples as you want to stress that a number next a variable, (or quantity) in this case, means to multiplication.
Ex. 2 Write an for
algebraic expression
Four times the difference of a number and six or
Agenda

11. Explore –Marvin's Math: Part 2
Marvin knows 30 fewer math tricks than his friend.
Here is the showing the number of tricks Marvin knows.
written expression
30 less than x
Here are 2 possible Algebraic Expressions. a) b)
Which is correct?
Lets go back to our basics to figure it out…
(Time on this slide - 2 min) Time passed 33 min
In-Class Notes
Read slide as it appears.
The discussion for this example on the next slide.
Preparation Notes
The purpose of this slide and the next slide is to introduce “less than”. However, to keep the consistency of Marvin the Magician, we chose this problem, therefore, “fewer” is the appropriate word. Clarification that fewer means less than is crucial for the next slide. Read the slide as it appears. Have student decided which expression they think is correct. Do not correct or discuss any possible reasoning. (This will take place in the next slide.)
Agenda

12. 20 50 - 30 42 72 - 30 26 56 - 30 x - 30 Explore –Marvin's Math: Part 2
1. What is 30 less than 50?
What did you do to get your answer?
2. What is 30 less than 72? 42
3. What is 30 less than 56? 26
Turn and Talk: When you see “less than” in a written expression, what is important?
4. What is 30 less than x?
x - 30
(Time on this slide - 5 min) Time passed 38 min
In-Class Notes:
Read the slide as it appears.
Advance the slide to see the answer and the process.
Before starting number 4, ask students questions similar to: Why is #4 different than the other problems? What is difficult in #4? Does the process change from problems #1-3 to #4?
Finish the problems then continue with the slide to have a discussion about the understanding of “less than”.
Preparation Notes:
The goal of this slide to clarify the misunderstandings of “less than”. (Be sure to connect the terminology to fewer than as well). Read the first question aloud to the students. Be sure to encourage them to write a mathematical expression that represents the written expression. The teacher can type in the numerical expression or write it on the slide. Continue with the next two problems. The fourth question is meant to challenge students to follow the process they used in the first three problems. Some questions to prompt student discussion: Why is #4 different than the other problems? What is difficult in #4? Does the process change from problems #1-3 to #4?
Advance the slide to discuss what is important when you see the word “less than?” (The numbers are switched).
Be sure to have students share their results incase some students struggled with this.
Agenda

13. 30 less than x a) b) Explore –Marvin's Math: Part 2
Marvin knows 30 fewer math tricks than his friend.
Here is the written expression showing the number of tricks Marvin knows.
30 less than x
Here are 2 possible Algebraic Expressions. a) b)
Correct Answer
(Time on this slide – 1 min) Time passed 39 min
In-Class Notes
Shows the correct expression.
Preparation Notes
This slide just shows the correct expression from the original problem.
Agenda

14. Practice- Class Work Class Work Lesson 4
Name__________________ Date____________
Class Work Lesson 4
1) Directions: Write an algebraic expression for each.
Let’s do the first one together.
a) five less than three times a number
b) eight less than the quotient of a number and two
c) nine times the sum of a number and fifteen
d) The sum of twice a number and seven
f) A number less than twenty five
e) one plus the product of a number and five
g) The sum of half a number and four
h) seven less than a third of the sum of a number and two
(Time on this slide – 12 min) Time passed 51 min
In-Class Notes
Hand out the class work assignment and read the directions.
Do the first problem with the students. Clicking the slide will make this appear.
Have students work in pairs to complete this assignment.
Allot time to go over the problems.
Preparation Notes
This is the class work assignment. Model the first problem with the class. Clicking the slide will show this in the lesson. Have students work in pairs on the worksheet. Circulate the room, checking to see if students have an understanding with the grouping symbols and also “less than”. Allot time to go over each example since this is the first time students are seeing this.
The next slide will allow you to click on the problem responses will appear.
2) Directions: Write two written expression for each. Use the key vocabulary. a) b)
Agenda

15. Practice- Class Work Class work lesson 4
Name__________________ Date____________
Class work lesson 4
1) Directions: Write an algebraic expression for each.
Let’s do the first one together.
a) five less than three times a number
b) eight less than the quotient of a number and two
c) nine times the sum of a number and fifteen
d) The sum of twice a number and seven
Important!!!!
Identify the
operation(s) by underlining key words.
f) A number less than twenty five
e) one plus the product of a number and five
g) The sum of half a number and four
h) seven less than a third of the sum of a number and two
In-Class Notes
This is a hidden slide to go over the first question.
Preparation Notes
2) Directions: Write two written expression for each. Use the key vocabulary. a) b)
Agenda

16. Practice- Class Work Summary
Name__________________ Date____________
Class Work Lesson 4
1) Directions: Write an algebraic expression for each.
a) Five less than three times a number
b) Eight less than the quotient of a number and two
c) Nine times the sum of a number and fifteen
d) The sum of twice a number and seven
e) One plus the product of a number and five
f) A number less than twenty five
h) Seven less than a third of the sum of a number and two
g) The sum of half a number and four
2) Directions: Write two written expression for each. Use the key vocabulary. a) b)
(Time on this slide - 5 min) Time passed 56 min
In-Class Notes
Click on the problem that you want to go over with the class.
Preparation Notes
This slide is to show the responses to all the problems on the class work. Click on the problem that you want to discuss and the work and response will appear after each click. c) d) e) f) g)
Agenda

17. Click to Return b) Eight less than the quotient of a number and two
Practice- Class Work Summary
Name__________________ Date____________
Class Work Lesson 4
1) Directions: Write an algebraic expression for each.
b) Eight less than the quotient of a number and two
In-Class Notes
Hidden slide for the class work.
Preparation Notes
Click to Return
Agenda

18. Click to Return c) Nine times the sum of a number and fifteen
Practice- Class Work Summary
Name__________________ Date____________
Class Work Lesson 4
1) Directions: Write an algebraic expression for each.
c) Nine times the sum of a number and fifteen
In-Class Notes
Hidden slide for the class work.
Preparation Notes
Click to Return
Agenda

19. Click to Return d) The sum of twice a number and seven
Practice- Class Work Summary
Name__________________ Date____________
Class Work Lesson 4
1) Directions: Write an algebraic expression for each.
d) The sum of twice a number and seven
Hidden slide for the class work.
Preparation Notes
Click to Return
Agenda

20. Click to Return e) One plus the product of a number and five
Practice- Class Work Summary
Name__________________ Date____________
Class Work Lesson 4
1) Directions: Write an algebraic expression for each.
e) One plus the product of a number and five
In-Class Notes
Hidden slide for the class work.
Preparation Notes
Click to Return
Agenda

21. Click to Return f) A number less than twenty five
Practice- Class Work Summary
Name__________________ Date____________
Class Work Lesson 4
1) Directions: Write an algebraic expression for each.
f) A number less than twenty five
In-Class Notes
Hidden slide for the class work.
Preparation Notes
Click to Return
Agenda

22. Click to Return g) The sum of half a number and four
Practice- Class Work Summary
Name__________________ Date____________
Class Work Lesson 4
1) Directions: Write an algebraic expression for each.
g) The sum of half a number and four
In-Class Notes
Hidden slide for the class work.
Preparation Notes
Click to Return
Agenda

23. Click to Return Practice- Class Work Summary
Name__________________ Date____________
Class Work Lesson 4
1) Directions: Write an algebraic expression for each.
h) Seven less than a third of the sum of a number and two
In-Class Notes
Hidden slide for the class work.
Preparation Notes
Click to Return
Agenda

24. a) Click to Return Ten minus a number A number less than ten
Practice- Class Work Summary
2) Directions: Write two written expression for each. Use the key vocabulary. a)
Ten minus a number
A number less than ten
Ten subtracted by a number
In-Class Notes
Hidden slide for the class work.
Preparation Notes
Click to Return
Agenda

25. b) Click to Return The sum of a number and nine, times ten
Practice- Class Work Summary
2) Directions: Write two written expression for each. Use the key vocabulary. b)
The sum of a number and nine, times ten
The sum of a number and nine multiplied by ten
Ten times the sum of a number and nine
In-Class Notes
Hidden slide for the class work.
Preparation Notes
Click to Return
Agenda

26. c) Click to Return Practice- Class Work Summary
2) Directions: Write two written expression for each. Use the key vocabulary. c)
Seven times the sum of a number and thirteen
Seven multiplied by the sum of a number and thirteen
The sum of a number and thirteen, times seven
In-Class Notes
Hidden slide for the class work.
Preparation Notes
Click to Return
Agenda

27. d) Click to Return Two times a number plus twelve
Practice- Class Work Summary
2) Directions: Write two written expression for each. Use the key vocabulary. d)
Two times a number plus twelve
Twice a number plus twelve
Twelve more than two times a number
In-Class Notes
Hidden slide for the class work.
Preparation Notes
Click to Return
Agenda

28. e) Click to Return A number divided by 10
Practice- Class Work Summary
2) Directions: Write two written expression for each. Use the key vocabulary. e)
A number divided by 10
The quotient of a number and 10
One-tenth of a number
In-Class Notes
Hidden slide for the class work.
Preparation Notes
Click to Return
Agenda

29. f) Click to Return Practice- Class Work Summary
2) Directions: Write two written expression for each. Use the key vocabulary. f)
Two divided by the difference of a number and thirteen
The quotient of two and the difference of a number and thirteen
In-Class Notes
Hidden slide for the class work.
Preparation Notes
Click to Return
Agenda

30. g) Click to Return Practice- Class Work Summary
2) Directions: Write two written expression for each. Use the key vocabulary. g)
A number times the difference of ten and another number
A number multiplied by the difference of ten and another
number
In-Class Notes
Hidden slide for the class work.
Preparation Notes
Click to Return
Agenda

31. Assessment-Exit Slip A number less than nine
Write an algebraic expression for
Three times the sum of a number and eight
2) Write a written expression for the algebraic expression using less than.
A number less than nine
3) Write an algebraic expression for
Ten less than the sum of a six and a number
(Time on this slide - 4 min) Time passed 60 min
In-Class Notes
Hand out the exit slip to each student.
Have student work individually for about 3 minutes.
Can either collect the exit slip or go over the answers on the click.
Preparation Notes
This is an exit slip to be given to the class as a lesson summary and then either collected or designed to go over before students leave the class. Answers are provided on the click if want to give students the correct responses.
Agenda