Ben Franklin's and the Magic Squares

My three-year-old loves to listen to books.  He often refers to things that he learned in one of the books we've recently read.  Knowing that he'll remember what he learns now, I went looking for some historical books to add to our library.  The Step into Reading series is well within his ability to comprehend, and a fun way to brush up on history for myself.





However, as we read through Ben Franklin and the Magic Squares by Frank Murphy for the first time, I realized that we had a small problem.  The climax of the story is Benjamin Franklin's invention of math puzzles based on addition, and my son hasn't started to add yet.

I decided to try to illustrate the value of the  Magic Squares using Duplos. The puzzles are three by three squares of numbers.  The rows, columns, and diagonal sequences can be added in any direction.  No matter which direction the numbers are added, the same sum is reached.  I had my son choose a row, then tell me the first number in the row.  We counted out that number of blocks all in the same color, and built them into a tower.  Then we went on to the next number in the row, counted out that number of blocks in a second color, and added them to our tower.  We finished  the row the same way.  Then I asked him to pick another row/or column and built another tower based on the second set of numbers.  By the time we finished the third tower, my son was impressed to see that all the towers were the same height.  He was also ready to go back to reading...