In the activity I would develop to explore the history of Arabic numerals I would first start by teaching a mini review of it. The numbers were represented by letters but not in the dictionary order. The system was known as huruf al jumal which meant "letters for calculating" and also sometimes as abjad which is just the first four numbers (1 = a, 2 = b, j = 3, d = 4). The numbers from 1 to 9 were represented by letters, then the numbers 10, 20, 30, ..., 90 by the next nine letters (10 = y, 20 = k, 30 = l, 40 = m, ...), then 100, 200, 300, ... , 900 by the next letters (100 = q, 200 = r, 300 = sh, 400 = ta, ...). There were 28 Arabic letters and so one was left over which was used to represent 1000. I would relate the lesson with operations and algebraic thinking when students have to use a variable(letter) to find the unknown. Once we have practiced how to solve a few problems I would then explain their independent activity. They will have to solve equations with a variable (letter) to solve the mystery picture.

-Nancy Tallas