/sci/ - Science & Math

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Anonymous Mon Jul 8 07:56:35 2019 No.10790288 [Reply] [Original]

HOW THE FUCK DO I MULTIPLY NUMBERS IN MY HEAD

>>	Anonymous Mon Jul 8 07:58:29 2019 No.10790291 >>10790288 multiplication is just addition

>>	Anonymous Mon Jul 8 07:59:36 2019 No.10790292 >>10790288 imagine you're writing out the multiplication on a piece of paper

>>	Anonymous Mon Jul 8 08:03:07 2019 No.10790297 >>10790288 You break them down to sums and use the distributive property.

>>	Anonymous Mon Jul 8 11:36:28 2019 No.10790588 Try the Trachtenberg system, developed by a smart guy while bored at camp. https://en.wikipedia.org/wiki/Trachtenberg_system

>>	Anonymous Mon Jul 8 12:57:56 2019 No.10790720 >>10790288 Rounding Then Left to right

>>	Anonymous Mon Jul 8 12:59:41 2019 No.10790723 >>10790288 >>10790720 Example: 789437 800400 320000

>>	Anonymous Mon Jul 8 13:03:12 2019 No.10790726 >>10790288 Learn Anzan

Anonymous Mon Jul 8 13:18:19 2019 No.10790755

>>10790288
Jesus christ OP I'm embarrassingly remedial in math and even I can multiply in my head.
Just use factors to break a big number into smaller numbers you can handle, or use visualization, I think about boxes stacked x to a layer, y layers tall. I picyure that in my head and add up the layers by the most convenient way.

>>	Anonymous Mon Jul 8 13:19:06 2019 No.10790757 >>10790288 Kek

>>	Anonymous Mon Jul 8 15:58:37 2019 No.10791023 I actually used to multiply 5 digit numbers in my head in high school. Tried recently, failed miserably. It's a matter of practice, probably.

>>	Anonymous Mon Jul 8 16:34:08 2019 No.10791088 >>10790288 put a calculator in your mouth

>>	Anonymous Mon Jul 8 16:36:06 2019 No.10791094 >>10790291 Iterated addition friend

>>	Anonymous Mon Jul 8 16:41:18 2019 No.10791099 >>10790288 say you wanna multiply 51232 Do 51230 + 5122 Or even 512101010 then add 512*2 It takes practice but it's easy to do

>>	Anonymous Mon Jul 8 16:43:27 2019 No.10791104 >>10791099 The general idea is that you get [eqn]a*b=a(b-n)+a(n)[/eqn]

>>	Anonymous Mon Jul 8 16:57:57 2019 No.10791122 >>10791099 >Or even 512101010 Don't you mean 51210*3? Kek.

>>	Anonymous Mon Jul 8 17:01:18 2019 No.10791126 >>10790288 WITH YOUR FEET IN THE AIR AND YOUR HEAD ON THE GROUND

>>	Anonymous Mon Jul 8 17:08:04 2019 No.10791139 File: 207 KB, 313x1183, 81DBD218-02A2-467C-B261-9BE39EE8F8EF.jpg [View same] [iqdb] [saucenao] [google] the duality of man

>>	Anonymous Mon Jul 8 17:46:13 2019 No.10791205 File: 51 KB, 700x610, 700px-Integer_multiplication_by_FFT.svg.png [View same] [iqdb] [saucenao] [google] Just memorize this and then do it in your head https://en.wikipedia.org/wiki/Schönhage–Strassen_algorithm

>>	Anonymous Mon Jul 8 17:49:32 2019 No.10791211 File: 870 KB, 350x559, dancanana.gif [View same] [iqdb] [saucenao] [google] >>10790288 Visuospatial sketchpad

>>	Anonymous Mon Jul 8 20:38:29 2019 No.10791676 >>10790288 82x28 80 * 20 = 1600 80 * 8 = 640 2 * 28 = 56 1600 + 640 + 56 = 2296

Anonymous Mon Jul 8 20:45:40 2019 No.10791694

>>10790288
learning how to add, memorizing all 36 of the non-zero single digit times tables, memorizing that 0 times anything is 0, memorizing that 1 times anything is said thing, memorizing that shifting numbers left/right will multiply/divide that number by 10, and you also need to dedicate enough short term memory to adding your digits together, and enough short term memory to retain the carried digits.

>>	Anonymous Mon Jul 8 21:13:41 2019 No.10791735 >>10790288 Slow hump= add. Smash and dash=multiply

>>	Anonymous Mon Jul 8 21:28:39 2019 No.10791778 >>10791122 No I just did it on my calc to make sure and it works

>>	Anonymous Mon Jul 8 21:30:27 2019 No.10791786 >>10791122 Oh wait shit my bad I thought you were asking something different and yeah your right I messed up

>>	Anonymous Tue Jul 9 00:18:16 2019 No.10792074 >>10791094 based and red-pilled

>>	Anonymous Tue Jul 9 00:52:29 2019 No.10792137 >>10791205 Very based. Gotta go fast

>>	Anonymous Tue Jul 9 05:01:13 2019 No.10792497 >>10790288 FFS anon, the state of you. Memorise your times table, it's something you have done when you were 7-9 years old.

>>	Anonymous Tue Jul 9 05:33:34 2019 No.10792544 File: 38 KB, 409x307, Boulier1.jpg [View same] [iqdb] [saucenao] [google] >>10790288 Practice on abacus! https://en.wikipedia.org/wiki/Mental_abacus

>>	Anonymous Tue Jul 9 12:11:31 2019 No.10793071 File: 72 KB, 900x900, 1560805214600.jpg [View same] [iqdb] [saucenao] [google] >>10791139

>>	Anonymous Tue Jul 9 13:11:19 2019 No.10793214 >>10792544 You should learn on a Soroban (4 beads below, 1 bead above) for mental abacus training

>>	Anonymous Tue Jul 9 13:14:17 2019 No.10793223 File: 601 KB, 2304x1728, 1556042566292.jpg [View same] [iqdb] [saucenao] [google] >>10791139

>>	Anonymous Tue Jul 9 13:31:58 2019 No.10793272 >>10791139 gay post

>>	Anonymous Tue Jul 9 15:47:08 2019 No.10793676 >>10790288 Just practice. Its fine if you are having a hard time. Most people cant multiply numbers bigger than 2 and 2 digits.

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