Grandma Wants to Know! Mom and Dad Cindy Grandma

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? Mom used a bar model Can you write an equation to represent Mom’s model? What number goes in each bar? How do you know? ______________________ 15 tickets________________ ______________________ 15 tickets_________________

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? Dad used a bar model too Can you write an equation to represent Dad’s model? ______________________ _________________ _______________________ 15 tickets ________________

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. “Cindy went to the carnival last night. She went on the same ride 5 times and used 3 tickets each time.” Dad said. What other strategy could Mom and Dad use to answer Grandma’s questions? Grandma asked, “How many tickets did she use each time she went on a ride?” Grandma asked, “How many tickets did Cindy use in all? 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. “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 she use each time she went on a ride?” Grandma asked, “How many tickets did Cindy use in all?

Our Array! dDDDD DDDDD DDDDd 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=____ 4 rows of ___=24 4 x ___=24 24 ÷ 6=___ 3 rows of ___=24 3 x ___=24 24 ÷ 3=___ 6 rows of ___=30 6 x ___=30 30 ÷ 6=___ What multiplication equation represents 6 rows of 5 equals 30? 6 x 5 = 30

More Practice!. 4 x ___= ÷ 4=___7 x ___= ÷ 7=___ Mrs. Jones buys 36 doughnuts for a class breakfast. She puts them on plates for her students. If she places 9 doughnuts on each plate, how many plates does Mrs. Jones use? Judy read 18 books during her summer break. She read the same number of books each month for 3 months. How many books did she read each month?

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.