Day 10.
I continue doing the position-numeric N-Back task. There wasn't much progress these days. I'm still on level 5.
There were some tough days on my main job, so I didn't have much time to work on mental math. I just added some basic statistics.
Doing mental math I noticed I now have a rate of 80% on the level 2.2 (two two-digit numbers) multiplication. The same 80% for the level 3.1 and about 30% for 3.2, which is far from desired target but acceptable by now.
Day 13
I continue doing position-numeric N-Back task.
Yesterday I started doing mental math exercises (not counting days I tested the task while developing). I'm doing only multiplication task, starting from 1.1 (two one-digit numbers) and advancing to the next level after each set I scored 80% or more.
I set maximum trial time to 60 seconds.
When I advanced to the level 3.2 I expected to fail most of the trials but surprisingly I made it with rate 70%.
What I like the most of these exercises is that I feel my brain is loaded for 100%. There is no place for distracting thoughts that sometimes make me fail the N-Back task. Even more, after finishing mental math exercise I feel so concentrated that I can do some N-Back sets better than ever.