1. Estimating Products and Quotients
Lesson 5.5
Estimating Products and Quotients

2. 1. 2
_ 3
2. 2
_ 5
3. 4
_ 7
4. 8
18. 5 _ 8
5. 6
_ 2
6. 7
_ 3
7. 4
_ 3 sections
8. 3
servings
9. 3
23. 6_8 ÷ 2_8 = 3 or 3_4 ÷ 2_8 = 3 or
10. 2 times
6_8 ÷ 1_4 = 3 or 3_4 ÷ 1_4 = 3
11. a. 2
24. 2_3 ÷ 1_3 = 2
b. 2
25. 7_8
c. 4
26. 4_9
d. 6
_ _15
12. 2 _ 3
__12
_ 7
_ 6

3. Warm-Up
1. 6 × ? = ? × 9 = What is of 20? 4. What is of 30? 12 7 15 10

4. Estimating Products and Quotients
Lesson 5.5
Estimating Products and Quotients
Estimate products and quotients using compatible numbers.

5. Good to Know!
Finding exact answers to problems involving multiplying and dividing fractions takes time and requires the use of paper and pencil. Compatible numbers are very important when estimating products and quotients. Compatible numbers are numbers that are easy to mentally compute. Example: and 24 are compatible numbers

6. Estimating Using Compatible Numbers
Use COMPATIBLE NUMBERS that are easier to compute with OR ROUND to the nearest whole number

7. Explore! 4-H Club
The Barnyard Critters 4-H Club held a fundraiser for their club. Each member raised money separately. The club leader collected all of the money. The pie chart to the right shows the fraction of the money spent on each type of animal the club members raise.
Step 1 Parrish collected $28 during the fundraiser. He wants to determine the
amount of his money that was spent on goats.
a. What calculation could Parrish do to find the exact answer?
b. Parrish wants to estimate the answer in his head. He changed the amount he collected to a number that is compatible with . Which number, 27 or 29, is more compatible with ? Why?
c. Use this number to determine the approximate amount of Parrish’s funds spent on goats.

8. Explore! 4-H Club
of the money raised by the 4-H club goes to pigs. Nichole raised $35. She wants to determine the amount of her money that will be spent on pigs.
a. What calculation could Nichole do to find the exact answer?
b. Nichole estimated the answer in her head. What whole number close to 35 is compatible with ? Why?
c. Use this number to determine the approximate amount of Nichole’s funds spent on pigs.

9. Explore! 4-H Club
EX Estimate each of the following calculations using compatible numbers. Explain in words why you chose the numbers you did.
a. b. c.

10. Example 1
Estimate the value of . The number 20 cannot be equally divided into sixths. List the multiples of 6.

11. Example 2
Johanna has a inch long piece of tubing for her science project. The project directions suggest cutting the tubing into inch long pieces. About how many pieces will she be able to cut?

12. Example 3
Jack needed about cups of dirt for each pot he was filling. He had pots left to fill. Approximately how much dirt does he still need?

13. Communication Prompt
Why would you want to estimate to find approximate answers for problems that include fractions or mixed numbers?

14. Exit Problems Estimate using compatible numbers.  14  8  25
Merrick had pounds of dog food. He ran a kennel and fed the dogs about pounds of food each day. About how many days can he use this bag of dog food before he runs out?
 14
 8
 25
about 8 days