Nice !

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Do you practise also with another operations?

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Nice work and explanation Benji!

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I practice 3 digits x 3 digits multiplications as well.

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Which method do you use for multiplication? How fast can you solve a 3x3 task?

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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.

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At this moment I solve 3 x 3 multiplications in 100 seconds.

It isnāt very fast indeed, so I need to train them more.

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I need for such task between 20 and 30sec. I have learned multiplication since 6 months. I use the soroban method for that.

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May I ask how does multiplication work on soroban?

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@flou you can find PDF books for free in Internet which explain with great examples how to solve multiplications with soroban.

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Itā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 donā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.

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Do you mean ten questions in 100sec, then itās quite decent.

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Yes, ten questions in 100 seconds.

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Why you can train only with addition but not subtraction? I mean donāt theyāre care for subtraction?

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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 āstruggleā, all the other operations caming naturally.

Its my opinion though, maybe other mental calculators have other opinion.

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Hi Benji, You donā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.

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@Silas_2001 @Antelex @flou when I try to be fast in 3 x 3 multiplications I do under 100 seconds, but I make mistakes. For example:

7/10 in 97.10 seconds, not bad, but not perfect.

@flou I wonder how seconds would take to Marc to complete this very taskā¦

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perfection is relativ! I also have done mistakes while calculation.

Donāt to be perfect because only god is it althought I donāt believe in god!

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well, we should do things very clear, we want to compete isnāt?

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