Tricks for multiplying large numbers

Recently I saw a video with a small trick for easily squaring a 2-3 digit number. Unfortunately I haven’t been able to find it again, but if you have seen the video with the trick somewhere feel free to link it in the comments or tell me about it if you just know the trick. It was really neat.

What I did find when I searched for it was another small trick for graphically multiplying large numbers, so this is what you get for now.

If you know some good tricks for making calculations easier when you are standing with a pen and a piece of paper, or just mental calculation. Please share them with me, it is so much easier than having to find a calculator for everything.

Posted by Kristian


Hi SuprDewd

Thanks for the link, it is awesome. Trick number 7 was exactly what I was looking for and the trick which from the video that disappeared for me.

Maybe some day I will actually be able to do mental math 🙂


I think you mean this channel on youtube:

but the videos are not complete because you’ll have to pay for that.

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