Analysis of the Squares: Trinomial

Age
6-9.

Materials

 * Box of colored bead bars 1-10
 * One each of the squares of 1-10
 * Rubber bands

Presentation

 * 1) This time we'll decompose the square in a different way.
 * 2) Count 3 along one side, and place the rubber band around the square.
 * 3) Count 3 along the other side and put on a rubber band.
 * 4) Now continue counting 5 more beads, and put a rubber band around.
 * 5) Do the same on the other side.
 * 6) Directress asks the child; "Into how many parts have we decomposed the square?".
 * 7) Observe how each of the 9 parts is composed.
 * 8) Notice the three squares which all lie on the diagonal, and the various rectangles formed.
 * 9) As before, we'll construct the squares as we write it all down.

3 x 3 = 09 3 x 5 = 15 3 x 2 = 06

30

5 x 3 = 15 5 x 5 = 25 5 x 2 = 10        +50

2 x 3 = 06 2 x 5 = 10 2 x 2 = 04       + 20        = 100

Control Of Error
Compute the sums of the three columns and add them together. Then slide all the bead bars toward the center, and place the 100-square on top. These are the two ways to prove that this equals one hundred.