1 / 16

Addition and Subtraction Mental, Informal, Standard written Method s

Addition and Subtraction Mental, Informal, Standard written Method s. We have little or no experience of teaching mental calculation in this country and a conspicuous dearth of publications recommending suitable tried and tested teaching strategies Thompson, 2000.

elam
Télécharger la présentation

Addition and Subtraction Mental, Informal, Standard written Method s

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. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Addition and Subtraction Mental, Informal, Standard written Methods

  2. We have little or no experience of teaching mental calculation in this country and a conspicuous dearth of publications recommending suitable tried and tested teaching strategies Thompson, 2000

  3. Key Messages – Mental Calculation • Involves rapid recall • Use of rapid recall facts and strategies to derive new facts • May involve pencil and paper jottings • Choice of strategy depends on the numbers involved, known facts and personal preference

  4. Their characteristics…. • feel for number • bank of known facts • range of strategies • can match strategy to calculation • can articulate and explain what they have done

  5. General Strategies • Counting on and counting back • Partitioning

  6. Particular Strategies • Reordering • Bridging • Near doubles • Compensation

  7. The benefits….. • reflects intuitive ways • in line with what we do naturally • promotes independent thinking • allows for discussion

  8. Number Line Images • 33 – 14 • 119 – 87 • £3.29 – £1.59 • Find how long between 4:30 and 9:15

  9. The ‘empty’ number line Addition: 54 + 36 278 + 158 Subtraction: 62 – 7 320 – 289 £6.26 - £5.90

  10. Informal written methods Addition • Expanded addition Subtraction • Counting up • Negative numbers

  11. Calculation skills should develop in such a way that a child first uses procedures which are rather long winded and even tedious compared with methods used by adults. However, these procedures are so designed that the child can see each step and can justify it at his own level of understanding. Lowry, 1965

  12. The ‘adult’ methods…..

  13. The ‘bugs’….

  14. Progression: Mental with jottings Non standard written methods Formal / compact / standard method

  15. Progression in Calculation “It seems unrealistic to expect that there will be a smooth progression from idiosyncratic mental methods to the standard written algorithms for the four basic operations” (Thompson, 1999, p. 170)

  16. Key Features of Standard Algorithms Plunkett • Written • Standardised • Contracted • Efficient • Automatic • Symbolic • General • Analytic • Not easily internalised • Encourage cognitive passivity Clarke • Traditional • Powerful • Reliable • Precise • Contracted • Fast • Provide a written record • Mental image • Instructive • Easy to mark and manage

More Related