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Bits and Pieces III Investigation 3.1 The Decimal Divide.

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Presentation on theme: "Bits and Pieces III Investigation 3.1 The Decimal Divide."— Presentation transcript:

1 Bits and Pieces III Investigation 3.1 The Decimal Divide

2 You will be able to:

3 GOALS Choose between division, multiplication, addition, or subtraction as an appropriate operation to use to solve a problem. Use models and the context to find solutions to division problems Estimate to find approximate solutions

4 In a grocery store, all of the scales measure in decimals. Explain or draw diagrams to show your reasoning for the following situations. Ricardo buys 3.2 ounces of a slice Italian ham called prosciutto to make sandwiches. Each sandwich uses one 0.4-ounce slice of prosciutto. How many sandwiches can he make?

5 What does the 3.2 and the o.4 in Question A part(1) represent? Ricardo buys 3.2 ounces of a slice Italian ham called prosciutto to make sandwiches. Each sandwich uses one 0.4-ounce slice of prosciutto. How many sandwiches can he make?

6 What does the 3.2 and the o.4 in Question A part(1) represent? Ricardo buys 3.2 ounces of a slice Italian ham called prosciutto to make sandwiches. Each sandwich uses one 0.4-ounce slice of prosciutto. How many sandwiches can he make? 3.2 represents the total ounces of prosciutto Ricardo bought and o.4 is how many ounces goes on a sandwich.

7 Write a number sentence solving this problem. Ricardo buys 3.2 ounces of a slice Italian ham called prosciutto to make sandwiches. Each sandwich uses one 0.4-ounce slice of prosciutto. How many sandwiches can he make?

8 Number sentence: 3.2 divided by 0.4 = 8 sandwiches This is done by making decimal numbers into whole numbers just like multiplication. 32 divided by 4 = 8 sandwiches this is the same mathematically as 3.2 divided by 0.4 = 8 sandwiches

9 Ms. Difanis buys 11.6 pounds of hamburger for a cookout. How many quarter-pound (0.25) burgers can she make?

10 What does the 11.6 and the 0.25 in Question A part(2) represent?

11 Ms. Difanis buys 11.6 pounds of hamburger for a cookout. How many quarter-pound (0.25) burgers can she make? What does the 11.6 and the 0.25 in Question A part(2) represent? 11.6 represents the pounds of hamburger she has 0.25 represents how much hamburger each individual patty or quarter pounder contains

12 Ms. Difanis buys 11.6 pounds of hamburger for a cookout. How many quarter-pound (0.25) burgers can she make? Write a number sentence solving the problem.

13 Ms. Difanis buys 11.6 pounds of hamburger for a cookout. How many quarter-pound (0.25) burgers can she make? 11.6 and 0.25, since 0.25 has two numbers to the right of the decimal than 11.6 has to have two numbers to the right of the decimal. THEN divided by 25 = 46.4 quarter-pound hamburgers NOTE: This is not the same as multiplying decimals. You must move the decimal over the same number of times in each factor.

14 11.6 divided by 0.25 = 46.4 What does the 0.4 in 46.4 represent?

15 11.6 divided by 0.25 = 46.4 What does the 0.4 in 46.4 represent? There are 46 quarters in 11.6 and o.4 left over, which means you can make 0.4 of another patty.

16 Why is division appropriate for these problems?

17 There is quantity that is being divided into parts of equal size.

18 Are the division situations in A(1) and A(2) sharing or grouping ?

19 These are sharing problems. For the first problem you find 0.4 slices you can get from 3.2 ounces and for the second problem you find 0.25 pattys you can make from 11.6 lbs of burger

20 Ashley eats five 5.25 ounce slices of watermelon in a contest at the the picnic. How many ounces of watermelon does she eat?

21 What operation do you use here? Estimate your answer.

22 Ashley eats five 5.25 ounce slices of watermelon in a contest at the the picnic. How many ounces of watermelon does she eat? What operation do you use here? Estimate your answer. You use multiplication Estimate 5 x 5 = 25

23 Stacey needs $39.99 for a pair of sneakers. She has $22.53 in her savings and a $15 check from babysitting. Can she buy the shoes?

24 What operation do you use here? Estimate your answer.

25 Stacey needs $39.99 for a pair of sneakers. She has $22.53 in her savings and a $15 check from babysitting. Can she buy the shoes? What operation do you use here? Estimate your answer. First add $23.00 and $15 to get $38, so then since $38 is less than $40. We can say she does not have enough money to buy the sneakers.

26 Li Mings allowance for transportation is $ How many times can she ride the bus if it costs $0.75 a trip? What operation do you use here? Estimate your answer.

27 Li Mings allowance for transportation is $ How many times can she ride the bus if it costs $0.75 a trip? What operation do you use here? Estimate your answer. You would use division here $12 divided by $1 = 12 rides 0r you could say multiplication since = =3 dollars = 4 trips then you could say 4 times what number is 12 the answer is 3 thus 4x3=12.


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