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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
We will begin by identifying the like terms to simplify the expression. Remember that only like terms — constant terms or terms with the same variable — can be combined. x + 31 + 5x - 2 In this case, we have two x-terms and two constants. Let's use the Commutative Property of Addition to rearrange the terms. Then we can combine them more easily.
Now the expression has one x-term and one constant. Since these terms cannot be combined further, the expression is simplified. We did it!
We will begin by identifying the like terms to simplify the expression. Remember, only like terms — constant terms or terms with the same variable — can be combined. 3.5c^2 + 8.5 + 14c - 0.5 - 12c - 13.5c^2 In this case, we have two c^2-terms, two c-terms, and two constants. Let's use the Commutative Property of Addition to rearrange the terms. Then we can combine them more easily.
Now the expression has one c^2-term, one c-term, and one constant. Since these terms cannot be combined further, the expression is simplified. We did it!
We want to know what value of x makes these expressions equivalent. Expression I: & 7a+10 -3a Expression II: & xa+10 Let's begin by simplifying Expression I. First, we will look for like terms — constant terms or terms with the same variable. Remember that only like terms can be combined. 7a + 10 - 3a We can see that there are two a-terms and one constant. Let's apply the Commutative Property of Addition to group these terms together and combine them.
Now let's compare these expressions. Expression I: & 4a+10 Expression II: & xa+10 We can see that if x has a value of 4, these expressions will be equivalent!
We want to know which value of x makes the given expressions equivalent. Expression I: & -19b+7+21b-2 Expression II: & 2b+x Let's start by identifying and grouping the like terms — constant terms or terms with the same variable. Remember that only these terms can be combined! -19b + 7 + 21b - 2 We can see that there are two b-terms and two constants. Let's apply the Commutative Property of Addition to group these terms together to combine them.
Now let's compare these expressions. Expression I: & 2b+ 5 Expression II: & 2b+ x We can see that the expressions will be equivalent if x has a value of 5. Therefore, 5 is the answer. We did it!
After school, Tiffaniqua and nine of her friends went to the bowling alley.
Tiffaniqua and nine friends went to the bowling alley. Eight members of the group paid $ p to play and an extra $ 5 to rent shoes. The remaining two friends only paid the $ p to play. We can find how much the friends paid as a whole paid by multiplying what each group paid by the number of people in that group.
Games and Shoe Rental | Games Only | |
---|---|---|
Price for One Person | p+5 | p |
Total | 8(p+5) | 2p |
Now that we have the amount of money paid by both group, we can add them together to find the total price the friends paid. Let's write this as an expression. 8(p+5)+ 2p This expression represents the total amount of money paid by the friends, but now we need to simplify it. First, let's use the Distributive Property. Then we can combine like terms to finish the simplification.
The total amount paid by the friends is $10p + 40.