# Spring SAVY 2020: Day 2 – Secrets of the Moli Stone (1st/2nd)

Saturday number two had students traveling all over the world!

With our overarching concept of systems, we continued to analyze the patterns, groupings, and symbols of different numeration systems. Our first stop was the Land of Treble! In the Land of Treble, everything is in groups of threes. From the tires on cars, to the toes on people’s feet, to the petals on flowers, and even a base three numeration system, you will find everything in a triad. The students LOVED exploring this mysterious land. Not only is the numeration system in base three, but there are silly names to go with each value. A group of ones is called a gickle, a group of three is called a bickle, a group of nine is called a rickle, and a group of twenty-seven is called a trickle! Kids loved saying these names throughout the day! Students were given a series of challenges they had to complete in order to travel back home. Each challenge had students experimenting and exploring the base three system more in depth. Level one had them adding gickles, bickles, and rickles in order to make a trickle! Just as we group by sets of ten in a base-ten system, other bases are grouped and traded in a similar way. Students learned to group and trade for another value in base three, and that the only digits in base three are 0,1, and 2. To pass level two, our mathematicians practiced subtracting in base three with the goal of having zero gickles on their boards. It was important for students to see that the grouping and renaming process is the same whether adding or subtracting, in base three or base ten. Finally, level three had students using both addition and subtraction where they applied regrouping and renaming skills. Once each pair complete these activities the entire class had to compare and contrast the base three and base ten system. They were very engaged as we tried to figure out the base three code for each of our numbers in base ten. For example, 27 in base ten would be equivalent to 1-0-0-0 (one, zero, zero, zero) in base three.

In the afternoon students ended up in Egypt. Just as they were given a series of challenges to complete in order to escape the Land of Treble, they were given a similar series of tasks in Egypt. We began by learning about the meaning of symbols and how we use them to represent numbers. Students needed to figure out the value of the seven different Egyptian symbols through analyzing a set of numbers with the corresponding Egyptian symbols. They learned how to read and write Egyptian numerals and then add and subtract quantities using these symbols. All of these activities lead them to think about the characteristics of our base-ten system and compare and contrast our numeration system to the Egyptian system. Students were fascinated with how many symbols it took to write a four-digit number! Did you know that 5,749 takes 25 Egyptian numerals to write? This is because numbers were created by repeating symbols of similar value so that the total number of symbols summed to a quantity. Our mathematicians also discovered there is no zero in the Egyptian number system or a symbol for anything larger than one million!

The ideas discussed in session two were very sophisticated. We concluded the day by taking the conclusions about the base three, Egyptian, and base ten systems and connecting them to our generalizations for systems!

We hope you’ll join us this Saturday for the parent open house at the end of the day!