What is speed of mental calculation at competition for numbers of given length? Also number to context memory system question

Mental Calculation, Mathematics, and Puzzles
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I would like to have reference point for my training. I am considering taking part in competition loosely, but anyway I would like to know what speed of fe. 1 by 1 multiplication should I strive for. There was a time when I trained but I think that I skipped to 3 digits operation too soon, and due to low basic speed as well as struggle to keep multiple digits in my head I stopped.

I trained a bit calculations with headphones on, but if there is no easly visible relation between digits I start to verbalise, or keep apropreated number in memory. That is another issue.

I was considering creation of memory system to improve number holding, but end up finding most natural returning to fact/place/relation where i saw that number. It works well but is inconsistent and would require me to make a list of numbers to context. If you have idea how to improve it I am open to suggestions.

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With students I coach in mental calculation (typically for their own personal interest rather than for competitions), I aim for sub-1.5 seconds for reading a 1-by-1 multiplication (such as 6 × 9), calculating (ideally from memory) and typing the answer. This means that the memory step is much less than one second.

As you’re aiming loosely towards being competitive, I’d aim for 1.0 seconds, so the memory step is almost instant.

This is of course only the first step to get fast at multiplications with many numbers. The next would be to know the cross-multiplication algorithm, or another equivalent one.

A later step is to reduce verbalization, as you suggested already in your post.

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