Do you practise also with another operations?
Nice work and explanation Benji!
I practice 3 digits x 3 digits multiplications as well.
Which method do you use for multiplication? How fast can you solve a 3x3 task?
With criss-cross technique.
And before that you do train additions a lot.
Well, in fact i think you must train additions all your life as human calculator.
At this moment I solve 3 x 3 multiplications in 100 seconds.
It isn’t very fast indeed, so I need to train them more.
I need for such task between 20 and 30sec. I have learned multiplication since 6 months. I use the soroban method for that.
May I ask how does multiplication work on soroban?
@flou you can find PDF books for free in Internet which explain with great examples how to solve multiplications with soroban.
It’s still good! I only can do this in 25sec because I still use the soroban instead to solve it only in my head because I still have to learn mental abacus. Currently its a little bit difficult for me to change the pictures in my mind fastly without forget the previous operations but otherwise i don’t have problems to imagine three row of beads. When I make an effort I can even imagine four rows of beads. Thats my current limit.
Do you mean ten questions in 100sec, then it’s quite decent.
Yes, ten questions in 100 seconds.
Why you can train only with addition but not subtraction? I mean don’t they’re care for subtraction?
I train only addition and multiplications at the moment. Then of course I will train square roots, cubic roots and divisions, which implies do subtractions.
Although mastering additions at a good level is the main “struggle”, all the other operations caming naturally.
Its my opinion though, maybe other mental calculators have other opinion.
Hi Benji, You don’t need to train them much, 15% of the total training time is enough. But do try division as early as possible. Your subtraction skill will increase at the same time.
7/10 in 97.10 seconds, not bad, but not perfect.
@flou I wonder how seconds would take to Marc to complete this very task…
perfection is relativ! I also have done mistakes while calculation.
Don’t to be perfect because only god is it althought I don’t believe in god!
well, we should do things very clear, we want to compete isn’t?