Transcript PowerPoint

Cindy
Grandma
Grandma Wants to Know!
Mom
and Dad
Mom and Dad have a problem!
Cindy went to the carnival last night. Mom and Dad are
telling Grandma how many rides Cindy went on and how
many tickets she used. Grandma is asking questions about
their stories. They each decided to use a different way to
explain it.
Mom said:
“Cindy went to the carnival last night. She rode the same
ride 5 times and used the same number of tickets each time.
She used 15 tickets in all.”
Grandma asked, “How many tickets did she use each time
she went on a ride?”
Let’s help Mom out!
“Cindy went to the carnival last night. She rode the same ride 5 times and used the same number of tickets each
time. She used 15 tickets in all.”
Grandma asked, “How many tickets did she use each time she went on a ride?”
What do you need to find?
______________________ 15 tickets_________________
Mom used a bar model
What number goes in each bar? How do you know?
3
3
3
3
______________________ 15 tickets________________
Can you write an equation to represent Mom’s model?
3
Grandma said:
I
Have
More
Questions!
Dad said:
“Cindy went to the carnival last night. She went on the
same ride 5 times and used 3 tickets each time.”
Grandma asked, “How many tickets did Cindy use in all?”
Let’s help Dad out!
Cindy went to the carnival last night. She went on the same ride 5 times and used 3 tickets each
time.”
Grandma asked, “How many tickets did Cindy use in all?
What do you need to find?
3
3
______________________
3
3
3
3
3
_________________
Dad used a bar model too
3
3
3
_______________________ 15 tickets ________________
Can you write an equation to represent Dad’s model?
What did we learn from Mom and Dad?
How do we know when to divide to solve a word problem?
When we have to find the number in each equal group or how many
equal groups.
How do we know when to multiply to solve a word problem?
When we have to find the total of equal groups.
Why is it possible to use multiplication to solve a division
problem?
Multiplication and division undo each other or are inverse operations if you know
2x6=12 you know 12÷6=2
Mom and Dad need more help!
“Cindy went to the carnival last night. She rode the same ride 5 times and used the same number
of tickets each time. She used 15 tickets in all.” Mom said.
Grandma asked, “How many tickets did she use each time she went on a ride?”
“Cindy went to the carnival last night. She went on the same ride 5 times and
used 3 tickets each time.”
Dad said.
Grandma asked, “How many tickets did Cindy use in all?
What other strategy could Mom and Dad use to answer Grandma’s questions?
An array
Show Mom and Dad how to make an Array!
Use your counters at your table to show Mom and Dad how to make an array to answer Grandma’s
questions. After you make your array draw it on your paper and label.
“Cindy went to the carnival last night. She rode the same ride 5 times and used the same number of tickets
each time. She used 15 tickets in all.” Mom said.
Grandma asked, “How many tickets did she use each time she went on a ride?”
“Cindy went to the carnival last night. She went on the same ride 5 times and used 3
tickets each time.”
Dad said.
Grandma asked, “How many tickets did Cindy use in all?
Our Array!
d
D
D
D
D
D
D
D
D
D
D
D
D
D
d
Do we have to make a different array for Mom and Dad’s stories?
No, we just explain it two different ways.
Mom would say Cindy had 15 tickets total she rode the
ride 5 times, therefore she used 3 tickets each time.
15÷5=3
Dad would say Cindy went on the same ride 5 times and used
3 tickets each so she used 15 tickets in all.
5x3=15
What are Inverse Operations?
The operation that undoes another operation.
Examples:
Addition (+) and Subtraction (-)
5+2=7
7-2=5
AND… What operations did we use to help Mom and Dad?
Multiplication (x) and Division (÷)
15÷5=3
5x3=15
This is how we can think about Multiplication to solve
Division.
Let’s Practice!
5 rows of ___=20
5 x____=20
20 ÷ 5=____
3 rows of ___=24
3 x ___=24
24 ÷ 3=___
4 rows of ___=24
4 x ___=24
24 ÷ 6=___
6 rows of ___=30
6 x ___=30
30 ÷ 6=___
6 x 5 = 30
What multiplication equation represents 6 rows of 5 equals 30?
More Practice!
.
4 x ___= 28 28 ÷ 4=___
7 x ___= 21 21 ÷ 7=___
Judy read 18 books during her
Mrs. Jones buys 36 doughnuts for a
class breakfast. She puts them on plates for her students. summer break. She read the same
If she places 9 doughnuts on each plate, how many plates number of books each month for 3 months.
How many books did she read each month?
does Mrs. Jones use?
What did we learn!
How can we use multiplication to divide?
Dividing is like the finding the factor we don’t know in
a multiplication problem. Use the product as the dividend
and one of the factors as the divisor. The other factor is
the quotient.