Colored Bead Bars: Inverse Products

Age
6-9.

Materials

 * Bbox of colored bead bars 1-10
 * Chart I

Presentation

 * 1) The directress asks the child to take the bar of 7, 6 times.
 * 2) The bars are lain in a column.
 * 3) Directress says: "How do we express this?"
 * 4) 7 x 6 = 42 is written down.
 * 5) Now, directress takes the bar of 6, 7 times.
 * 6) These are lain next to the others.
 * 7) When the child writes down 6 x 7 =42, he should observe that the product was the same.
 * 8) Directress says: "Are the multiplication problems the same? Notice that the two rectangles are equal, each having 42. even though the order of the factors is not the same".
 * 9) The child should observe in the written form that the factors are the same, just reversed in their positions.
 * 10) Directress gives several examples of this.

Purpose

 * To help the child on the memorization of multiplication understanding of the commutative property of multiplication.