5-Minute Check 1) 5 x 7 2) 7 x 70 3) 9 x 20 4) 4 x 800 5) 6 x ) The each person to eat for one week is $200. Find the total cost for a family of 5 to eat for one week. 1) 5 x 7 2) 7 x 70 3) 9 x 20 4) 4 x 800 5) 6 x ) The each person to eat for one week is $200. Find the total cost for a family of 5 to eat for one week.

Mental Math: Estimate Products

Objective F By the end of this lesson, you will be able to estimate products by rounding factors and using easier numbers and then finding the product mentally. F Essential Question: What strategies can you use to multiply by a 1-digit number? F N.S Round whole numbers through the millions to the nearest ten, hundred, thousand, ten thousand, or hundred thousand. F By the end of this lesson, you will be able to estimate products by rounding factors and using easier numbers and then finding the product mentally. F Essential Question: What strategies can you use to multiply by a 1-digit number? F N.S Round whole numbers through the millions to the nearest ten, hundred, thousand, ten thousand, or hundred thousand.

Explore F What is a reasonable estimate for 6 x 22? F Talk with your table to find an estimate for 6 x 22. Think about what you have learned yesterday about multiplying by ten.

Explain F Anyone willing to share their strategies? F Do you think the exact answer for 6 x 22 is greater or less than your estimate? Why? F Explain why finding an estimated answer is sometimes better than finding an exact answer. F Anyone willing to share their strategies? F Do you think the exact answer for 6 x 22 is greater or less than your estimate? Why? F Explain why finding an estimated answer is sometimes better than finding an exact answer.

More Examples F Try these problems: F 3 x 38 F 5 x 78 F 7 x 42 F Try these problems: F 3 x 38 F 5 x 78 F 7 x 42

Problem F An African elephant is the largest living land mammal. It uses its trunk to pick up objects that weigh up to three times as much as a 175-pound person. About how much weight can an African elephant pick up with its trunk? F Step 1 - Round the greater factor to the nearest hundred. F 3 x 175 F 3 x 200 F Step 2 - use mental math. F 3 x 2 = 6 (basic fact) F 3 x 20 = 60 F 3 x 200 = 600 F An African elephant is the largest living land mammal. It uses its trunk to pick up objects that weigh up to three times as much as a 175-pound person. About how much weight can an African elephant pick up with its trunk? F Step 1 - Round the greater factor to the nearest hundred. F 3 x 175 F 3 x 200 F Step 2 - use mental math. F 3 x 2 = 6 (basic fact) F 3 x 20 = 60 F 3 x 200 = 600

Another Problem F In one day, an African elephant eats 9 bags of food. Each bag weighs 57 pounds. How many pounds of food does the elephant eat? F 9 x 57 F Use mental math. F 9 x 6 = 54 (basic fact) F 9 x 60 = 540 F In one day, an African elephant eats 9 bags of food. Each bag weighs 57 pounds. How many pounds of food does the elephant eat? F 9 x 57 F Use mental math. F 9 x 6 = 54 (basic fact) F 9 x 60 = 540

F 5 x 7,441 F 7 x $6.68 F 9 x 820 F 4 x 32 F 7 x 98 F 5 x 7,441 F 7 x $6.68 F 9 x 820 F 4 x 32 F 7 x 98 F 3 x 415 F 6 x $3.25 F 9 x 6,221 F 6 x 281 F 4 x 2,509

Assignment F Blue Group – Blue Page F Everyone else – page #’s 9-25 F Get them all correct - no Math homework F Blue Group – Blue Page F Everyone else – page #’s 9-25 F Get them all correct - no Math homework