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| 9 Theory slides |
| 10 Exercises - Grade E - A |
| Each lesson is meant to take 1-2 classroom sessions |
Here are a few recommended readings before getting started with this lesson.
Determine whether the terms are like terms.
Once like terms are identified, it is possible to combine them using addition or subtraction.
Heichi got a part-time summer job at a local history museum. He asked his sister for directions from home to the museum. She drew a map for him. She also knows that Heichi is studying algebraic expressions, so she used algebraic expressions to show the relevant distances.
Heichi is trying to determine the overall distance from his house to the museum along the route his sister marked for him. The route is broken into three separate sections. Each section has a unique length represented by a unique algebraic expression.
Section | Expression |
---|---|
First Leg | x |
Second Leg | 3x+7 |
Third Leg | 4x−6 |
Commutative Property of Addition
Add terms
Subtract term
On weekends, the museum has special admission prices before noon.
Children pay x dollars and adults pay x2 dollars before noon. After noon, the prices go up to y and y2 dollars for children and adults, respectively. Heichi kept track of the number of visitors on both Saturday and Sunday in separate tables. The following table shows the number of visitors on Saturday.
Saturday's Visitors | ||
---|---|---|
Children | Adults | |
Before Noon | 7 | 12 |
After Noon | 12 | 20 |
The table below shows the number of visitors on Sunday.
Sunday's Visitors | ||
---|---|---|
Children | Adults | |
Before Noon | 8 | 15 |
After Noon | 3 | 4 |
Remember that the tickets have different prices depending on the time of day.
Saturday's Visitors | |||
---|---|---|---|
Children ($) | Adults ($) | Total ($) | |
Before Noon | 7x | 12x2 | 7x+12x2 |
After Noon | 12y | 20y2 | 12y+20y2 |
Sunday's Visitors | |||
---|---|---|---|
Children ($) | Adults ($) | Total ($) | |
Before Noon | 8x | 15x2 | 8x+15x2 |
After Noon | 3y | 4y2 | 3y+4y2 |
Commutative Property of Addition
Add terms
Heichi's friend Magdalena works at the souvenir shop in the museum. There are three large items that are sold in the shop.
Magdalena told Heichi that three groups of people visited the shop on Saturday.
Start by writing an expression for Saturday. Then, multiply that expression by 2.
Start by writing an expression to find the amount of money made by the store on Saturday. Consider each group separately.
The money exchanged for each set of items is the product of the number of items sold and its corresponding price. Note that when an item is returned, the prices are negative because money is being taken from the shop and returned to the customer.
Vases ($) | Plush Toys ($) | Paintings ($) | Total ($) | |
---|---|---|---|---|
First Group | 3a | 4b | 5c | 3a+4b+5c |
Second Group | -2a | 6b | 1c | -2a+6b+1c |
Third Group | 1a | 0 | -1c | 1a−1c |
Commutative Property of Addition
Add terms
Subtract terms
Distribute 2
Multiply
Davontay and his friends want to get ice cream.
Their favorite place, the Ice Cream Home, has the following prices.
Ice Cream Home Menu | |
---|---|
Item | Price ($) |
Medium Ice Cream Sundae | x |
Large Ice Cream Sundae | 2x |
add 1 topping | add $1.00 |
add 2 toppings | add $1.50 |
add 3 toppings | add $2.00 |
The friends placed the following order.
We are given the menu for ice cream sundaes at the Ice Cream Home. Prices vary depending on the size and number of toppings on the sundae.
Ice Cream Home Menu | |
---|---|
Item | Price ($) |
Medium Ice Cream Sundae | x |
Large Ice Cream Sundae | 2x |
add 1 topping | add $ 1.00 |
add 2 toppings | add $ 1.50 |
add 3 toppings | add $ 2.00 |
We want to find the an expression for how much money the friends paid for their ice cream. Let's review their order.
The friends can be divided into four groups based on their orders. Let's write the price of a single order from each group and then multiply these by the number of people who made that order. We can organize the information in a table.
Price of a Single Order ($) | Total Group Price ($) | |
---|---|---|
Group 1 | x+2.00 | 2(x+2) |
Group 2 | 2x+1.00 | 1(2x+1) |
Group 3 | x+1.50 | 4(x+1.5) |
Group 4 | x | 3x |
Now that we have an expression for each different order, we can find the total by adding all the expressions. 2(x+2)+ 2x+1 + 4(x+1.5) + 3x Let's simplify this expression. Remember to use the Distributive Property to simplify the terms between parentheses first.
Now that we have used the Distributive Property, we need to group like terms and add them. Let's do it!
The group paid a total of $11x+11 for the entire order. We did it!
Ali wants to create on a short film for a festival. He decides to rent the equipment he needs. The cost to rent the equipment is shown below.
Item | Daily Rental Cost ($) | Down Payment ($) |
---|---|---|
Camera Kit | 300 | 150 |
Audio Kit | 250 | 100 |
Lighting Kit | 100 | 30 |
We are told that Ali needs to rent equipment for d days to shoot a short film. We are asked to write an expression that can be used to represent the total cost. Let's take a look at the cost of each piece of equipment.
Item | Daily Rental Cost ($) | Down Payment ($) |
---|---|---|
Camera Kit | 300 | 150 |
Audio Kit | 250 | 100 |
Lighting Kit | 100 | 30 |
Let's start by finding the total cost of renting the camera kit for d days. The rental fee is $ 300 per day. If Ali wants to rent the camera kit for d days, he will pay the product of d and $ 300. 300 d However, that is not the whole fee. Ali will also need to pay an additional down payment of 150. Let's add this to our expression. 300 d + 150 This is the total cost to rent the camera kit for d days. Let's write the costs of the other pieces of equipment in a similar way. We can organize this information in the table.
Item | Daily Rental Cost ($) | Down Payment ($) | Cost for d Days ($) |
---|---|---|---|
Camera Kit | 300 | 150 | 300 d + 150 |
Audio Kit | 250 | 100 | 250 d+ 100 |
Lighting Kit | 100 | 30 | 100 d+ 30 |
Finally, let's add the costs of each piece of equipment to write an expression for the total cost of the rental. Remember to group the like terms together to combine them and simplify the expression.
Ali will have to pay $650d+280 to be able to shoot his dream project. Good job!
Consider the following rectangle.
We are asked to write an algebraic expression for the perimeter of the given rectangle. Let's take a look at the figure.
The perimeter of a figure is the sum of all its side lengths. We are only given the length of two sides, but remember that a rectangle has two pairs of sides of equal length. Let's fill in the rest of the diagram.
We can multiply each both lengths by 2 and add the products to find the perimeter. Remember to use the Distributive Property.
The perimeter of the rectantle is 9z+2. We did it!