Zero

1
Zero
0
0

• What is it?
• Whats it good for?

0
0
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 thats your score in a game
• When thats how much money you have and you want
  to buy something
• When thats the number of times youve won at a
  game
• So zero can be a bad number!

5
When is zero a good thing to have?

• When thats the number of cavities you have when
  you visit the dentist
• When thats how many times youve been in trouble
• When thats the number of times youve 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 dont!

• 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 0s stand for?
• How do we write the number thirteen
• 13
• Why not 013 or 0013?

7
Zeros history

• The Romans didnt have a number named zero.
• Hundreds of years ago, if a number didnt 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

Another symbol we use for zero
Ø
9
Is zero the lowest number there is?

• 0 is less than 2 or 1
• But it isnt the lowest number!
• Sometimes the temperature is below zero!
• So 0 isnt 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 youve
  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 cant 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 cant be done.

17
Hard subtraction problems involving 0
1 9 9
12

• 2 0 0 2
• - 2 8

4
7
1 9
18
Hard subtraction problems involving 0
4 9
17

• 5 0 7
• - 8 9

8
1
4
19
Hard subtraction problems involving 0
16
4 9 9

• 5 0 0 6
• -2 6 2 8

8
3
7
2
20
Shortcuts for multiplying numbers ending in zero

• 80
• X 60

• Multiply the non-zero digits

Count the number of zeros

• Add this many zeros to the end of the answer

48
00
21
Shortcuts for multiplying numbers ending in zero

• 800
• X 90

• Multiply the non-zero digits

Count the number of zeros

• Add this many zeros to the end of the answer

72
000
22
Shortcuts for multiplying numbers ending in zero

• 200
• X 60

• Multiply the non-zero digits

Count the number of zeros

• Add this many zeros to the end of the answer

12
000
23
You can use this trick to help you estimate
answers.
About how much would 21 bikes cost if each bike
costs 399.00?

• The actual answer is 21 x 399

• To approximate the answer, round the numbers off

• 400
• X 20

• Multiply the non-zero digits

Count the number of zeros

• Add this many zeros to the end of the answer

8
000
24
You can use this trick to help you estimate
answers.
About how many hours are there in the month of
May?

• The actual answer is 24 x 31

• Round the numbers off

• 20
• X 30

• Multiply the non-zero digits

Count the number of zeros

• Add this many zeros to the end of the answer

6
00
25
You can use this trick to help you estimate
answers.
About how many days do you go to school from
kindergarten through 12th grade?

• The actual answer is 13 x 180

• Round the numbers off

• 200
• X 10

• Multiply the non-zero digits

Count the number of zeros

• Add this many zeros to the end of the answer

2
000
26
I hope youve 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.