Commutative Law

of Multiplication

Material

  • Bead bars. 
  • Use of symbols ‘x’ and ‘=’.

Direct aim

  • To permit the child to discover the Commutative Law of multiplication (ab=ba) in a sensorial way.
  • It is also a further aid for the memorization of tables.
  • The child has already met this law in addition, there should not be any great difficulty.

Age of great interest

5 to 6 years.

Presentation

  1. Write a sum for the child,e.g. 5×4=       .
  2. Ask him to do it with the bead bars. Suggest that he tries doing 4×5.
  3. It is interesting for the child if you show him the similarity of the rectangles formed by the layout of the beads.

Exercise with the bead bars

Material

  • A quantity of the coloured beads.
  • Prepared slips (for individual work).

Examples of prepared slips:

9 x 5 =  [picture] 4 x 6 = [picture]

N.B.:This also helps the child to understand that the multiplier is not a solid quantity.