Monday, December 19, 2011

Exponential learning

Austin and Skye have been working through the Khan exercises on exponents this week. He's been doing pretty well but Skye thought an exercise to make things more visible might help him get a better idea of what exponents "look like." 


This was the result (photo). 






They hand-calculated about 1/2 of the numbers seen on this wall. This was great practice in multiple-digit addition and multiplication. Once they got to the higher numbers Skye showed him how to calculate exponents using a scientific calculator.

It didn't take him long to first notice how quickly numbers grow when you move from one base to another (somewhere around 3^6) and then the interesting relationships between base 2, base 4, base 8 and base 16.

They took a short detour into computer science to discuss how computers are based on a base 2 number system.

Fun!



For base-9 digits, Skye showed Austin that he can reduce every solution to 9, by adding up the digits and reducing them until only a single digit remains. For example, the solution to 9^9 is 387,420,489. 3+8+7+4+2+0+4+8+9 = 45; 4+5 = 9! This way, Austin can double-check to see if he has calculated the correct result.


Carla showed Austin that he can do the same for base-3 digits, and the final result will be 3, 6 or 9 (all multiples of 3).


Austin is enjoying exponents so much, that he has been teaching the concept to Aidan. Aidan is a good sport about it and is enjoying finding patterns on the grid.


I overheard Austin encouraging Aidan at one point. I hadn't heard what Aidan said, but I heard Austin say, "You ARE smart! You found patterns that even I hadn't noticed!" This teaching experience has been good for their relationship. In fact, I've noticed that they are getting along better, overall, these days. Hope it's not only because Santa's watching ;)

Tuesday, December 13, 2011

Exponents

Austin's been working on exponents ... X squared, x cubed, x to the y, x to the negative y, x to the 1/2 (square-root), multiplying exponents that have the same base, fractional exponents and scientific notation.

This was all done on Khan Academy lessons:
- exponents 1
- exponents 2
- exponents 3
- exponents rules 1
- scientific notation