Transcript Bits and Pieces III Investigation 3.1 The Decimal Divide You will be

Bits and Pieces III
Investigation 3.1
The Decimal Divide
You will be able to:
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
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?
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?
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?
What does the 3.2 and the o.4 in Question A part(1)
represent?
3.2 represents the total ounces of
prosciutto Ricardo bought and o.4 is
how many ounces goes on a sandwich.
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?
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?
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
Ms. Difanis buys 11.6 pounds of
hamburger for a cookout. How many
quarter-pound (0.25) burgers can she
make?
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?
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
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.
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.
THEN1160 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.
11.6 divided by 0.25 = 46.4
What does the 0.4 in 46.4 represent?
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.
Why is division appropriate for these problems?
Why is division appropriate for these problems?
There is quantity that is being divided into
parts of equal size.
Are the division situations in A(1) and A(2)
sharing or grouping ?
Are the division situations in A(1) and A(2)
sharing or grouping ?
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
Ashley eats five 5.25 ounce slices of watermelon
in a contest at the the picnic. How many ounces
of watermelon does she eat?
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.
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
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?
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.
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.
Li Ming’s allowance for transportation is $12.45.
How many times can she ride the bus if it costs
$0.75 a trip?
What operation do you use here? Estimate your
answer.
Li Ming’s allowance for transportation is $12.45.
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 0.75 + 0.75 = 1.50 + 1.50 =3 dollars =
4 trips then you could say 4 times what
number is 12 the answer is 3 thus 4x3=12.