Review: Multiplying by Powers of Ten

Find the products for the following combinations.

5 x 4 =

5 x 40 =

5 x 400 =

10 x 10 =

100 x 10 =

1000 x 10 =

What do you notice about the number of zeroes in the factors and in the product?

So… once you find your Best Friend Basic Fact, then you just have to add the zeroes in the problem to the end

of your answer?Let’s see: 8 x 2= 16So- what is 8 x 20

Last summer, Mrs. Norcel entered a raffle and won 36 computers for the school! If she

wants to divide them equally, how many will each class get?

Think about this problem and how would you Go about solving it. Use all your strategies.

Oh no! I made a mistake! Mrs. Norcel was lucky enough to get 360 new computers to give out. She still is

going to divide them equally into 9 class rooms. How many computers will

the lucky classroom get now?

Mrs. Norcel has 36 new computers to give out. If she wants to divide them equally into 9

classrooms, how many new computers will the lucky classrooms receive?

Work these problems.Do you see your answer/product listed below?

50 x 40 = 8000 x 500 =

200

2,000

20,000

40,000

400,000

4,000,000

Work these problems.Do you see your answer/product listed below?Be sure to underline the basic facts product,

then add the zeroes!50 x 40 = 2,000 8000 x 500 = 4,000,000

200

2,000

20,000

40,000

400,000

4,000,000

# of zeroes + # of zeroes=product # of zeroes

The Basic Fact is our “BF” best friend!

50 x 50 = 600 x 60 =

400 x 400 = 7000 x 70 =

800 x 800 = 3000 x 3 =

Mrs. Norcel has 36 new computers to give out. If she wants to divide them equally into 9classrooms, how many new computers will the lucky classrooms receive?

…

Oh no, I made a mistake, Mrs. Norcel was lucky enough to get 360 new computers to give out. She still is going to divide them equally into 9 classrooms.How many computers will the lucky classroom get now?

Mrs. Norcel has 36 new computers to give out. If she wants to divide them equally into 9classrooms, how many new computers will the lucky classrooms receive?

Focus: Dividing by Multiples of 10

Problem: Suppose I have $100 that I want to share equally with 10 friends. How much money will each friend receive?

How can you prove that your answer is correct?

Let’s keep track of our equations and waysto check on the small whiteboard.

Problem: Suppose I have $1,000 that I want to share equally with 10 friends. How much money will each friend receive?

How can you prove that your answer is correct?

Problem: Suppose I have $10,000 that I want to share equally with 10 friends. How much money will each friend receive?

How can you prove that your answer is correct?

Look at all the problems we just completed.Talk about the pattern of “zeros” you see with the division problems.

Now think back to the multiplication problems. How are the patterns similar and different?

Questions to Discuss

Can you “connect” this to what you know aboutFAMILY OF FACTS? Are the BASIC FACTS STILL YOUR BEST FRIEND WHEN DIVIDING?

Let’s apply what we’ve learned.

1. 600 ÷ 2 =

2. 600 ÷ 20 =

3. 600 ÷ 200 =

4. 8,000 ÷ 4 =

5. 8,000 ÷ 40 =

6. 8,000 ÷ 400 =

7. 12,000 ÷ 300 =

8. 240,000 ÷ 3,000 =

9. 56,000 ÷ 80 =

10. 6,400,000 ÷ 800 =

11. 420,000 ÷ 6,000 =

12. 36,000,000 ÷ 40,000 =

PRACTICE MAKES PERFECT!!

Directions for the activity: 1. Pull out a basic fact card.2. Write the basic fact and solve in the first column of the chart.3. One person rolls the dice. What ever amount you roll is the

amount of zeros you add to the first number in the basic fact.4. The next person rolls the other dice. What ever number you

roll is the amount of zeros you add the other number in your problem.

5. Write your new problem down and solve. 6. Be sure to think about what you learn of multiples of 10.