3X3 multiplication in 3.2 sec

It’s my last update on 33 & 6/3 series.
Recently I got several 95-100 seconds on 10 sets of 5
5 for the first time, so it seems to be the right time to switch to higher digits entirely. Will continue to update when getting some new progress.

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Nice!


Can I ask, since I’m not familiar with the Memoriad software (they don’t have a Mac version)… do you have any control over the numbers that get selected?

There are four instances with a zero, such as 302, 203, 902, and 202. Is that by design? I mean for the last question (334x202) that basically just means: double the number and add the same number with a shifted decimal point. Even the 189 to the left of it is just 100-10-1 so all you gotta do is add two zero and then shift and subtract twice the number that is already there.

I still think you got a nice score… but somehow it seems the problems are deliberately chosen by the software so that shortcuts can be applied. Maybe I’m just seeing patterns where there aren’t any. Anyways, I’m not questioning your skills at all… just curious about the software.

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Bjeorn, I guess you’re just better than most mental calculators at finding these patterns! At the speed that flou is working (3 operations per second) it’s fastest to brute-force the numbers with cross-multiplication rather than to scan for patterns.

This is one reason I like verbal mental math—doing e.g. 3×3 multiplications without seeing the numbers means that shortcuts like you describe really do help. However for speed multiplication above 2×2 I almost always use the rather bland cross-multiplication.

The world record is around 4 operations per second for multiplication (Marc Jornet Sanz, 10 questions of 8×8 in 163 seconds) so @flou , this time is very impressive! Note however, that with larger multiplications the operations get harder (basically recalling a 1×1 multiplication from memory and adding in onto a (larger) running total).

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Thanks for your questions Bjoern! (Sorry for my bad English)
To my observation, there are no such control I think? I’m not quite sure though, maybe @Daniel360 could offer some nicer insights.
But I know that the digits generate by the software don’t have 0 on the first and the last digits, so it would be harder than a randomly generated one I think.

The 0s are indeed a little too much. I selected this score from around 10 scores, it is the highest and easiest one. Most of the time I got 28-32 points I think.

I think shortcuts would make me even slower in these tests, because I might need to think about which shortcuts I should chose to tackle these problems. I personally use the vertical method.

Thanks again!

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Thanks for your reply Daniel!!

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Hi @Josh, I have a littleeeee question about the pending post mechanism.
When

The post mentioned above is pending until 3 hours ago. @Daniel_360, whom I asked for help, has already given an answer before that time :joy:
This is a little confusing sometimes…Maybe a time stamp of the sending time could be added to the post.
That’s it, thanks for the help!

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Sorry about that. It isn’t easy to rearrange the order of the posts above, but I’ve fixed things so that it shouldn’t happen again.

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Very nice!

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Hi @Daniel_360, I have some little suggestions for the memoriad software(non-competition version).

I. To click the [finish] button on the result page, one have to use a mouse. I wonder if it could be done by press the keys on keyboard, since it is quite tiring to reach for the mouse more than a hundred times a day.

II. The theme color of the software is blue, and blue light can easily lead to eye fatigue. If the color can be customized, It would be better I think.

III. The minimum concentration time is 3 sec currently, I think it is a little too long for daily practicing, maybe 1 sec or even 0 is more appropriate.

Thanks for your listening.

@flou , I agree with all of your suggestions—especially the first one about using a keyboard shortcut to stop the timer—but I’m not in any way involved with the development of this software, so there’s nothing I can do to help.

You might pass on your ideas to Melik Duyar and his team, who manage the Memoriad software.

Since I do actually develop my own training tools, there’s a small chance I have something different to help you. What category(ies) are you training?

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Thanks for your help Daniel!
I train multiplication, division and flash anzan.

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You can use this training tool if you like: Exact Divisions. I made it as while setting up some other things, including the Spring Challenge on World Mental Calculation, which is Decimal Division.

I can add more digits to the Exact Divisions tool if anyone needs.

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Thanks for your recommendation Daniel