# Blog on Brain Training

Today is the 5-th day I started experiment with the N-Back task (numeric) and mental math calculations. For Numeric N-Back I use Dual N-Back task with position and numeric signals.

First 5 days I only used the N-Back task.

Recently I started an experiment on the mental math training. But before the experiment details I'd like to have a few words on why I decided to do the mental math exercises at all.

I always liked the ability to operate big numbers in mind. Multiplication of two two-digit numbers mentally was possible but took a lot of time, multiplication of two three-digit numbers seemed as something unreachable. When I tried to do it I met some insuperable barriers like forgetting intermediate results in the process of calculation or some mental distractions that led me to loosing focus on the task.

At the same time I felt I could do it after some trainings that will allow me to expand my working memory limits and stay more focused. By that time I have already been doing N-Back task for a while and reached the Dual 7-Back level. So, I decided to add mental math exercise to the site. I also decided to make an experiment on how long will it take me to be able to multiply two three-digit numbers in mind.

I started doing Dual N-Back from level 2. It was hard. My D2B rate was about 50% those days. In a couple of months of constant trainings I reached the 7-th level. That may seem great for beginners and not a big deal for some advanced n-backers. Doing that exercises I acquired some good training experience. I also read about how N-Back should and should not be done. So, here I gathered some advices for you.