Review: Multiplying by Powers of Ten
Find the products for the following combinations.
5 x 4 =
10 x 10 =
5 x 40 =
100 x 10 =
5 x 400 =
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= 16
So- what is 8 x 20
Think about this problem and how would you
Go about solving it. Use all your strategies.
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?
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
40,000
2,000
400,000
20,000
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
40,000
2,000
400,000
20,000
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 9
classrooms, 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 9
classrooms, how many new computers will the
lucky classrooms receive?
Focus: Dividing by Multiples of 10
Let’s keep track of our
equations and ways
to check on the small white
board.
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?
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?
Questions to Discuss
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?
Can you “connect” this to what you know about
FAMILY OF FACTS? Are the BASIC FACTS
STILL YOUR BEST FRIEND WHEN DIVIDING?
Let’s apply what we’ve learned.
1. 600 ÷ 2 =
7. 12,000 ÷ 300 =
2. 600 ÷ 20 =
8. 240,000 ÷ 3,000 =
3. 600 ÷ 200 =
9. 56,000 ÷ 80 =
4. 8,000 ÷ 4 =
10. 6,400,000 ÷ 800 =
5. 8,000 ÷ 40 =
11. 420,000 ÷ 6,000 =
6. 8,000 ÷ 400 =
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.