1. Splash Screen

2. Five-Minute Check (over Lesson 3–7) Main Idea
Example 1: Estimate with Money
Example 2: Greater Numbers
Lesson Menu

3. I will multiply to solve problems involving money and greater numbers.
Main Idea/Vocabulary

4. Estimate with Money
Kitty wants to buy 4 boxes of cereal that cost $3.54 each. She has $16. Does she have enough money to buy the cereal?
$3.54 × 4 $4
× 4
Round $3.54 to $4 because $3.54 is closer to $4 than to $3.
$4 × 4 = $16
Multiply mentally.
Answer: So, the total cost of the cereal is about $16. Since the cost was rounded up, Kitty should have enough money.
Example 1

5. Lynnelle wants to buy 5 cans of soup that cost $2. 18 each
Lynnelle wants to buy 5 cans of soup that cost $2.18 each. Estimate the total cost of the soup?
$7.00
$8.00
$10.00
$15.00 A B C D
Example 1

6. Estimate the product of 5.9 and 25. 5.9 × 25
Greater Numbers
Ramon averages 5.9 yards each time he runs the football. If he runs the ball 25 times in a single game, about how many yards will Ramon run?
Estimate the product of 5.9 and 25.
5.9 × 25
6 × 25 = 150 Round 5.9 to 6.
6 × 25 = 150 Multiply.
Answer: So, 6 × 25 is about 150. Ramon will run about 150 yards.
Example 2

7. A gallon of gasoline costs $3. 10. Jacob’s car holds 12 gallons
A gallon of gasoline costs $3.10. Jacob’s car holds 12 gallons. About how much will it cost Jacob to buy 12 gallons of gasoline?
$25
$36
$42
$45 A B C D
Example 2

8. Greater Numbers
Use the calculator feature from your Math Tool ChestTM to find 228 × 50.
Estimate 228 × 50 ≈ 200 × 50 or 10,000
Example 3

9. Greater Numbers Enter: Press: Enter: Press: Solution:
Answer: So, 228 × 50 = 11,400.
Example 3

10. Check for Reasonableness
Greater Numbers
Check for Reasonableness
The estimate, 10,000 is less than 11,400. But one of the original numbers was rounded down. So, it is reasonable to expect that the estimate would be less than the exact answer.
Example 3

11. Use the calculator to find 391 × 60.
23,460
19,550
17,595
14,354 A B C D
Example 3

12. End of the Lesson
End Lesson

13. Five-Minute Check (over Lesson 3–7) Image Bank Math Tool Chest
Multiply Mentally
Resources

14. Associative Property; 554 Associative Property; 500
(over Lesson 3–7)
Use properties of multiplication to find 4 × 25 × 5 mentally. Show your steps and identify the properties you used.
Associative Property; 554
Associative Property; 500
Commutative Property; 500
Commutative Property; 554 A B C D
Five Minute Check 1

15. Commutative Property; 7,000
(over Lesson 3–7)
Use properties of multiplication to find 50 × 35 × 4 mentally. Show your steps and identify the properties you used.
Commutative Property; 7,000
Commutative Property and Associative Property; 7,000
Associative Property; 7,525
Commutative Property; 7,025 A B C D
Five Minute Check 2

16. Commutative Property; 6,600 Commutative Property; 6,000
(over Lesson 3–7)
Use properties of multiplication to find 6 × 50 × 22 mentally. Show your steps and identify the properties you used.
Commutative Property; 6,600
Commutative Property; 6,000
Associative Property; 6,600
Associative Property; 6,000 A B C D
Five Minute Check 3

17. Commutative Property and Associative Property; 1,240
(over Lesson 3–7)
Use properties of multiplication to find (8 × 31) × 5 mentally. Show your steps and identify the properties you used.
Commutative Property and Associative Property; 1,240
Commutative Property; 1,240
Associative Property; 1,420
Commutative Property and Associative Property; 1,420 A B C D
Five Minute Check 4

18. End of Custom Shows