How to Multiply

Today you'll learn how to multiply big, huge numbers just knowing how to count, and add.
This system is as easy that any kid should learn it, because it's totally graphical. So, let's go!



*EDIT: Thanks to mrmucox for noticing about the formatting problem, now it's solved ;)

Step 1 Drawing the First Number

Ok, let's say we want to multiply 37 * 51. We all know that if we take our calculator, and multiply, we'll get 1887. Now, we'll forget about using calculators, and we'll take a notebook and some pens. So, our first number is 37. As its first digit is 3, we'll draw 3 diagonal straight lines (from the left-lower corner, to the right upper corner). Now, we'll draw 7 lines (for the second digit, a 7), a little bit below the first ones (look at the pictures).

Comments

[Spypro]

I have some interesanting thing to do with these system, to work with tose hudge numbers, but mentally and the limit is actually the efficency of persons immaganative cortex, so if you are interesated?

[genknight]

its nice but I don't think its so practical since the normal way is actually doing that what you do here. besides , drawing those lines is more time consuming too. all the kid needs to do is learn the multiplication table up to 9 and be able to add. this is nice in the beginning to learn the multiplication table but it shouldn't be used too often cause then it'll be a crutch later on.

37
x 51

---

7 (1x7=7)
3 (1x3=3)
35 (5x7=35)
+ 15 (5x3=15)

---

1887

[genknight]

drat , i lost the formatting

[zemalc01]

What about zero's? Do you just add in a line that's all 000000's?

[The Dark Ninja]

I agree, can you provide some info on how to multiply numbers like 30*27?

[naught101]

why do you add the 0s on the start of the lower numbers (038 and 0007 in the example)? It would make more mathematical sense to add them to the end of the higher numbers (to get the monospace formatting, use {{{ on the line before, and }}} on the line after the stuff you want monospaced):

1500 380   7+

[naught101]

http://www.instructables.com/id/Instructables_Text_Formatting/#step5
more detailed explaination

[cutting Matt]

why don't my teachers teach me this? i could just sit at home reading instructables instead of going to school!

[ratolibre1]

We all'd do the same ;)

[mrmucox]

I think you lost some formatting on steps 3 and 4. Instructables removes multiple spaces. I think you meant

15
038
0007

---

1887

AND

6
20
017
0025
00004

---

81954

[ratolibre1]

Thanks! I edited it as soon as I read your comment. Didn't notice about the problem ;)

[nagutron]

Word. That is much clearer, mrmucox.