Multiplication

 

  • Chinese method is really just rote learning.
  • Grid method is promoted in primary schools.
    • Good because it can be introduced by counting the number of squares, so promotes understanding of the size of a multiplication problem.
    • For example: 14 x 12

Screen Shot 2013-08-11 at 10.07.25

Total = 100 + 40 + 20 + 8 = 168

  • You can also expand brackets using the grid method:
    • 32 x 41 is equivalent to (30 + 2) (40 + 1)
    • (x + 2)(x + 1)

Screen Shot 2013-08-11 at 10.07.34

So the answer is x2 + 3x + 2

    • This can be extended to negative numbers, but you need to make clear that the operations are the same.
    • N.B. Students will tend to say 2x rather than x2. Scaffold using: 2×2=22, 3×3=32, 4×4=42
  • You can also use the grid method to explore the difference of two squares (but its even better using geogebra!)

One thought on “Multiplication

  1. Pingback: Summer Institute highlight: An amazing day on number | Weekly Maths

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