slide1
Download
Skip this Video
Download Presentation
Learning objective: To be able to use partitioning to double or halve numbers.

Loading in 2 Seconds...

play fullscreen
1 / 15

Place value - PowerPoint PPT Presentation


  • 295 Views
  • Uploaded on

Learning objective: To be able to use partitioning to double or halve numbers. . Place value. Numbers are categorised as being either units/ones, tens, hundreds or thousands etc. The position of the digit within an number shows its value according to its ‘place’.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Place value' - Audrey


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

Learning objective:

To be able to use partitioning to double or halve numbers.

place value
Place value
  • Numbers are categorised as being either units/ones, tens, hundreds or thousands etc.
  • The position of the digit within an number shows its value according to its ‘place’.
  • In whole numbers the number on the far right is always the units/ones column, next on the left comes the tens, then the thousands etc.
partitioning
Partitioning
  • Partitioning is the breaking down of a number into several components according to its place value.
  • E.g. 485 = 400 + 80 + 5
  • The zeros represent a place holder of the other digits ( e.g. tens and units) and without them the number would simply look like a single unit of 4.
  • ..\..\..\..\Desktop\Maths ITP\placevalue_pc.EXE
partitioning and doubling
Partitioning and doubling
  • Why do we need to partition when doubling?
  • By partitioning a number we can use known doubles of smaller numbers and then add these together to calculate the answer.
  • E.g. double 47 is not a double that most people know of by heart.
slide6
BUT of you partition it into tens and units

( 40 + 7)

Double 40 is relatively easy = 40x 2 = 80

Double 7 is a known double = 7 x 2 = 14

Add these together  80

+14

94

slide7
Have a go at this calculation using your knowledge of partitioning and known doubles.

Q. What is double 67?

partitioning and halving
Partitioning and halving
  • Why do we need to partition when halving?
  • By partitioning a number we can use known halves of smaller numbers and then add these together to calculate the answer.
  • E.g. half of 58???????????
slide10
Partition 58 into tens and units

(50 + 8)

  • Half of 50 = 25 ( ½ or divide by 2)
  • Half of 8 = 4
  • Add these together  25

+ 4

29

slide11
Have a go at this calculation using your knowledge of partitioning and known halves.
  • Q. What is half of 38?
slide13
Remember  if the number you are halving is an even number it will always halve exactly.
  • Whereas if the number is an odd number the answer will always have the fraction of a half in it ( e.g. half of 13 = 6 ½ )
  • The easiest way to halve odd numbers is to half the even number just before it and then add on a half to that number (e.g. 13  half of 12 is 6 + ½ = 6 ½ )
slide15
Main activity:
  • With your partner, roll 2 dice to find 2-digit numbers. Then partition them into tens/units and find the doubles/halves and record in your exercise books.
  • E.g. 34  30 + 4
  • 30 = 60 = 15
  • 4 = 8 = 2
  • Therefore 34 = 68 (60 + 8) = 17 (15 + 2)
  • Please remember to write the long date along with the title. LO: To be able to use partitioning to double or halve numbers.
  • Year 3’s to work on numbers between 1-50 first (x 10) then go onto numbers 50-100. ( x 5)
  • Year 4’s to work on numbers between 1-100. (x 10)
  • Extension: roll dice 3 times to create 3-digit numbers and find doubles/halves by partitioning into hundreds/tens/units (x 5)
ad