**Total Time – The full 5 hours**

**Total Cost – None**

The inspiration for this weeks challenge came from a video I saw on children in Japan who used a “Mental Abacus” to perform advanced math in their heads. These kids were so familiar with the abacus that they didn’t even need one in front of them to use it – they moved their fingers around in the air as they pictured an abacus in their mind.

Unable to multiply 2 digit numbers together in my head, I decided to set the goal for this project to 3 by 3 digit mental multiplication. It took me every minute of the 5 hours to be able to do it, but I’m happy to report that I’m now able to multiply 3 digit numbers together without anything but by brain and some nifty tricks. I’m counting this project a victory, but in truth I’m only about 80-90% accurate with 3 by 3 digit multiplication as I write these words. I feel very confident that I could get that number up to 99% with another week or two of regular practice, but that time would be falling outside the 5 hour restriction of 5 and 50. You can watch me do 3 by 3 digit multiplication in the video below:

Having never used an Abacus before, my quest began by watching videos on how to use the Soroban, the Japanese equivalent of the Abacus. The Soroban is a very simple device to grasp, each column of beads is there so you can quickly represent and manipulate single digits during math operations. Before learning how it worked I assumed that the Soroban enabled you to do some nifty tricks and shortcuts when multiplying large numbers together, but I quickly found out that device was more of a replacement for pen and paper than it was for a calculator.

The true beauty of the Soroban was the process it uses for multiplication, which can you see in the video below:

**bold**. The key here is to try to think of things that are as strange, disgusting, and memorable as possible. It might be easy to forget the mental image of your neighbor Karl mowing the lawn, but you probably aren’t going to forget the image of Adolf Hitler waving a sex toy around while skydiving. Choose celebrities or fictional characters that are very distinct, actions that will easily stick out in your memory, and locations that you can place yourself in. You can see that I chose “ro”, the Korean word for street to represent my third digit 0. As I currently live in Korea, it is very easy for me to picture one of the narrow and busy Korean streets near my apartment. I can smell the smells, hear the sounds, and see the brightly colored signs on all the buildings. Try to chose locations where you can do the same thing.

- Unless you’re extremely familiar with the Abacus/Soroban, don’t screw around with trying to picture one in your head. I probably wasted 30 minutes or more on trying to do this.
- Its
*much*easier to multiply 2 and 3 digit numbers when you can see the numbers you’re multiplying together written down in front of you. Though it might be tempting to start out by having the numbers written down in front of you, I recommend learning 2 by 2 digit multiplication entirely in your head. It will seem tricky at first but I promise you can do it if I can – my memory skills are below average at best. You’ll need to learn how to do it without paper eventually, and I think its better to start that process sooner than later. - In 2 by 3 and 3 by 3 digit multiplication, start out by looking at the numbers you’re multiplying together before moving on to doing it in your head. Essentially, do the opposite of what I said to do in the previous step. You dont want to get bogged down in the added complexity of the additional digits to remember and operations to keep track of, so make sure you master the process first.
- If you have a better way of keeping track of the digits in your head than picturing them on your fingers, go for it! The finger method was what worked for me but everyone’s mind works differently. I’m a kinesthetic learner (movement or action based learning), but you might be a visual or auditory learner. Use whatever method works best for you.

That’s all for now! For week three of “New Skills Month” I’ll be looking to lighten things up a little bit by attempting to learn something a little less serious. I’ve always been jealous of people who can raise one eyebrow like an evil villain, especially Stephen Colbert:

I have huge, Greek, bushy eyebrows, but completely lack the ability to use them nefarious expressions. NO LONGER!!!

See you next week,

Aleco Pors