(7.2) Number, operation, and quantitative reasoning.

The student adds, subtracts, multiplies, or divides to solve problems and justify solutions.

The student is expected to: (F) select and use appropriate operations to solve problems and justify the selections.

7.2F Problem Solving

Solve problems that involve fractions and decimals using the same steps as any other problem.

7.2F INSTRUCTIONAL ACTIVITY #1

EXAMPLE: Torie has 9 cans of salmon. If each can holds 14.5 ounces, how many ounces of canned salmon does Torie have?

UNDERSTAND: First, make sure you understand the problem. Identify the quantities involved and the relationships between them.

There are 9 cans of salmon. Each can holds 14.5 ounces.

PLAN: Write an equation that can be used to find the answer to the problem.

To combine the equal groups, use multiplication. The total ounces of canned salmon = 9 x 14.5

Solve problems that involve fractions and decimals using the same steps as any other problem.

7.2F INSTRUCTIONAL ACTIVITY #1

EXAMPLE: Torie has 9 cans of salmon. If each can holds 14.5 ounces, how many ounces of canned salmon does Torie have?

SOLVE: Solve the equation.

14.5x 9130.5

LOOK BACK: Check your answer to see if it is reasonable.

Since 9 x 14.5 is close to the product of 10 and 14, which is 140. The answer 130.5 seems reasonable.

There is one decimal place to the right of thedecimal point in the two factors. Therefore, therewill be only one decimal place to the right of thedecimal point in the product. The product of 9and 14.5 is 130.5.

Torie has a total of 130.5 ounces of canned salmon.

7.2F STUDENT ACTIVITY #1

Problem #1: Marcus has 3 ¼ pounds of birdseed in a container. He also has a bag with 2.5 pounds of birdseed in it. If Marcus pours half the birdseed from the bag into the container, how much birdseed will be in the container?UNDERSTAND

First, make sure you _________________ the problem. Identify the _________ involved and the _________________ between them.

• One container of birdseed contains ______ pounds.• A bag of birdseed contains ______ pounds.• The 2.5 pounds of birdseed needs to be divided into ______ equal parts.• That amount and the amount of birdseed in the _______________ need to be combined.

PLAN

Write an ________________ that can be used to find the ______________ to the problem. To separate the birdseed in the bag into two equal parts, use the operation of _____________.

______ ÷ ______ = ______

Use the operation of ____________ to find out how much birdseed will then be in the container.

______ + ______ = amount of birdseed in the container

understand quantitiesrelationships

3 ¼ 2.5

twocontainer

equation answerdivision

2.5 2 1.25

addition

3 ¼ 1.25

7.2F STUDENT ACTIVITY #1

Problem #1: Marcus has 3 ¼ pounds of birdseed in a container. He also has a bag with 2.5 pounds of birdseed in it. If Marcus pours half the birdseed from the bag into the container, how much birdseed will be in the container?SOLVE

Solve the ________________.

Convert 3 ¼ to an equivalent _______________.

3 ¼ = ______

______ + ______ = ______

The container will have _________ pounds of birdseed in it.

LOOK BACK

Check your answer to see if it is reasonable. Since ____________ of the birdseed in the bag is over ____ pound, but not over ____ pounds, and the container originally had a little over ____ pounds of birdseed, the new amount in the container will be more than _____ pounds, but not over _____ pounds. The answer _______ seems reasonable.

equation

decimal

3.25

3.25 1.25 4.5

4.5

1.25 pounds1 2 3

45 4.5

7.2F STUDENT ACTIVITY #1

Problem #2: Missy has 7.5 school days until her research paper for science class is due. If she writes 2.5 pages each school day, how many pages will she write before the paper is due?

UNDERSTAND

First, make sure you _________________ the problem. Identify the _________________involved and the _________________ between them.

• There are _____ days until the paper is due.• Each day Missy writes _____ pages.

PLAN

Write an _______________ that can be used to find the answer to the ________________.To combine the equal groups, use the operation of _______________________.

The total number of pages = _____ x _____

understand quantitiesrelationships

7.52.5

equation problemmultiplication

7.5 2.5

7.2F STUDENT ACTIVITY #1

Problem #2: Missy has 7.5 school days until her research paper for science class is due. If she writes 2.5 pages each school day, how many pages will she write before the paper is due?

SOLVE

Solve the _________________.Show your work to solve the problem in the space below.

There is _________ decimal place to the __________of the decimal point in each of the twofactors. Therefore, there will be ___________ decimal places to the _________ of the decimal point in the product. The product of 7.5 and 2.5 is ____________.

LOOK BACK

Check your answer to see if it is ____________________.7.5 x 2.5 is close to the product of 7 and 2, which is ______. Each of the decimal numbers were rounded _____, so ________ seems to be a reasonable answer.

Missy will write a total of ________ pages for her science research paper.

equation7.5

x 2.55

2

370

1

15+18.75

one righttwo right

18.75

reasonable14

down 18.75

18.75

7.2F STUDENT ACTIVITY #1

Problem #3: Mitzi bought 4 ½ pounds of lean ground beef in a package. She had another 1.75 pounds of ground beef in a container in the refrigerator. Mitzi decided to use half the lean ground beef from the package to make meat for tacos, and she combined the remainder of the ground beef from the package to the container in the refrigerator to make hamburger patties for another meal. How much ground beef will be in the container in the refrigerator when she combines the remainder of the beef from the package?

UNDERSTANDFirst, make sure you __________ the problem. Identify the _________ involved and the _________________ between them.

The package of ground beef contains ________ pounds. The container of ground beef in the refrigerator has ______ pounds. The 4 ½ pounds of ground beef in the package needs to be _____________ into _____ equal parts. That amount and the amount of ground beef in the container need to be ___________________.

understand quantitiesrelationships

4 ½ 1.75

divided twoadded

7.2F STUDENT ACTIVITY #1

Problem #3: Mitzi bought 4 ½ pounds of lean ground beef in a package. She had another 1.75 pounds of ground beef in a container in the refrigerator. Mitzi decided to use half the lean ground beef from the package to make meat for tacos, and she combined the remainder of the ground beef from the package to the container in the refrigerator to make hamburger patties for another meal. How much ground beef will be in the container in the refrigerator when she combines the remainder of the beef from the package?

PLAN

Write an _______________ that can be used to find the _________________ to the problem.

To separate the ground beef in the package into two equal parts, use the operation of________________.

______ ÷ ______ = x = = ___

Use the operation of ________________ to find out how much ground beef will then be in thecontainer in the refrigerator.

______ + ______ = amount of beef in the container in the refrigerator.

equation answer

division

4 ½ 29

2

1

2

9

42

1

4

addition

2 ¼ 1.75

7.2F STUDENT ACTIVITY #1

Problem #3: Mitzi bought 4 ½ pounds of lean ground beef in a package. She had another 1.75 pounds of ground beef in a container in the refrigerator. Mitzi decided to use half the lean ground beef from the package to make meat for tacos, and she combined the remainder of the ground beef from the package to the container in the refrigerator to make hamburger patties for another meal. How much ground beef will be in the container in the refrigerator when she combines the remainder of the beef from the package?SOLVE

Solve the _________________.

Convert 2 ¼ to an equivalent __________________.

2 ¼ = _______

______ + ______ = ______

The container in the refrigerator will have _________ pounds of ground beef in it.

equation

decimal

2.25

2.25 1.75 4

4

7.2F STUDENT ACTIVITY #1

Problem #3: Mitzi bought 4 ½ pounds of lean ground beef in a package. She had another 1.75 pounds of ground beef in a container in the refrigerator. Mitzi decided to use half the lean ground beef from the package to make meat for tacos, and she combined the remainder of the ground beef from the package to the container in the refrigerator to make hamburger patties for another meal. How much ground beef will be in the container in the refrigerator when she combines the remainder of the beef from the package?LOOK BACK

Check your answer to see if it is ______________________.

Since ________ of the ground beef in the package is over ____ pounds, but less than ____pounds, and the container in the refrigerator originally had over ____ pound, but less than ____pounds of ground beef, the new amount in the container will be over _____ pounds, but less than_____ pounds.

The answer _______ seems reasonable.

reasonable

half 2 31 2

25

4