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#### Presentation Transcript

**1. **Zero What is it?
What’s it good for?

**2. **Is zero a number or is it just nothing? How many students in this room have blue eyes?
How many students in this room are wearing glasses?
How many students in this room have two noses and three ears?
Zero IS a number!

**3. **Where is zero used? As a place holder: 1,204
As a score in a game: 3 - 0
As a grade if you miss every problem!
In phone numbers: 540-896-8956
In money: $100.00

**4. **When is zero a bad thing to have? When that’s your score in a game
When that’s how much money you have and you want to buy something
When that’s the number of times you’ve won at a game
So zero can be a bad number!

**5. **When is zero a good thing to have? When that’s the number of cavities you have when you visit the dentist
When that’s how many times you’ve been in trouble
When that’s the number of times you’ve lost at a game
So zero can be a good number, too!

**6. **Zero can be a mysterious number! Sometimes we write it, sometimes we don’t! How do you write the number: twenty?
20
What does the 0 stand for?
How do you write the number: two thousand six
2006
What do the 0’s stand for?
How do we write the number: thirteen
13
Why not 013 or 0013?

**7. **Zero’s history The Romans didn’t have a number named zero.
Hundreds of years ago, if a number didn’t have any tens then a blank space was put in. For example, one hundred three was written 1 3
Can you see the problem this created?
Around the year 650 a mathematician from India thought to use 0 to be a place holder.

**8. **Other terms we use for zero Zilch
Nothing
Nought

**9. **Is zero the lowest number there is? 0 is less than 2 or 1
But it isn’t the lowest number!
Sometimes the temperature is below zero!
So 0 isn’t the lowest number.

**10. **Is zero even or is it odd? These numbers are even: 8, 6, 4, 2
These numbers are odd: 9, 7, 5, 3, 1
If we follow this pattern, 0 will be in the first group--it is EVEN.

**11. **Adding with 0 The addition facts with 0 are the easiest facts to learn!
3 + 0 = 3
0 + 8 = 8
What is 1,234 + 0 ?
What is 0 + 9,876 ?
What is ? + 0 ?
How about 0 + ? ?

**12. **Subtracting with 0 Subtraction with 0 is a little trickier!
What is 3 - 0 ?
What is 0 - 8 ?
What is 4,123 - 0 ?
What is ? - 0 ?
How about 0 - ? ?

**13. **Multiplying with 0 Multiplication with 0 is easy!
What is 5 x 0 ?
What is 0 x 7 ?
What is 0 x 0 ?
What is 4,123 x 0 ?
What is 56 x 87 x 97 x 0 ?
What is ? x 0 ?
How about 0 x ? ?
If you multiplied together all the numbers you’ve ever used in your lifetime, would the answer be large or small?

**14. **Dividing with 0 What does division mean?
144 ÷ 8 means what do we multiply 8 by in order to equal 144 (16)
7714 ÷ 29 means what do we multiply 29 by in order to equal 7714 (266)
0 ÷ 3 means what do we multiply 3 by in order to equal 0
What is 0 ÷ 5 ?
What is 0 ÷ 123 ?

**15. **Dividing by 0 How about 5 ÷ 0 ?
This would mean what do we multiply 0 by in order to equal 5
Nothing would work!
So we say that 5 ÷ 0 can’t be done.
If you try it on a calculator you will get an error message.

**16. **What is 0 ÷ 0 ? Follow this pattern…
3 ÷ 3 = 1
2 ÷ 2 = 1
1 ÷ 1 = 1
So 0 ÷ 0 = ??
But follow this pattern…
0 ÷ 3 = 0
0 ÷ 2 = 0
0 ÷ 1 = 0
So 0 ÷ 0 = ??
Actually no one knows what 0 ÷ 0 is. So we say it can’t be done.

**17. **Hard subtraction problems involving 0 2 0 0 2
- 2 8

**18. **Hard subtraction problems involving 0 5 0 7
- 8 9

**19. **Hard subtraction problems involving 0 5 0 0 6
-2 6 2 8

**20. **Shortcuts for multiplying numbers ending in zero 80
X 60

**21. **Shortcuts for multiplying numbers ending in zero 800
X 90

**22. **Shortcuts for multiplying numbers ending in zero 200
X 60

**23. **You can use this trick to help you estimate answers. 400
X 20

**24. **You can use this trick to help you estimate answers. 20
X 30

**25. **You can use this trick to help you estimate answers. 200
X 10

**26. **I hope you’ve seen that zero is ALL of these: It is a number
It is an even number
It is a small number but not the smallest number there is
It is useful as a place holder in numbers like 10,004
It is easy to calculate with as long as you avoid dividing by it
It is useful in doing calculations
It is a very important number!

**27. **As a number, zero is a hero! Thanks for your attention.