Math Is Fun Forum

NotAMathLover

Member

Registered: 2007-09-16

Posts: 2

PLEASE HELP ME!!! I beg you!!

Hi!

Well, here is my story...really simple. I did not pay attention to math in the past and now the consequences I must suffer.

Does anyone know any good methods for multiplication. I mean like simple multiplication, stuff you learn in the 3rd grade. I can multiply by nines if I use the finger trick, I can multiply by 5's if I count in my head. If I try to commit them to memory, I get anxious and test myself but when I do, I do not know them.

There must be some fun and easy methods.

bossk171

Member

Registered: 2007-07-16

Posts: 305

Re: PLEASE HELP ME!!! I beg you!!

how about http://www.mathsisfun.com/tables.html

The game is actually pretty fun.

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There are 10 types of people in the world, those who understand binary, those who don't, and those who can use induction.

MathsIsFun

Administrator

Registered: 2005-01-21

Posts: 7,713

Re: PLEASE HELP ME!!! I beg you!!

Start here: Multiplication - Times Tables

And that page has links to other (hopefully useful) pages.

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"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

NotAMathLover

Member

Registered: 2007-09-16

Posts: 2

Re: PLEASE HELP ME!!! I beg you!!

Thanks!

Devantè

Real Member

Registered: 2006-07-14

Posts: 6,400

Re: PLEASE HELP ME!!! I beg you!!

I have a very advanced method for multiplying together numbers of any digits, be them the same amounts of digits or different amounts of digits. Let us take 42*37;

42
37
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There are 3 steps to this. For three-digit numbers there would be 5, for four there would be 7, for five there wold be 9 and so on. First, multiply the units together; 2*7.

42                  1
37
----
  4

(making a note of the 1) What we just did there was the first step of my method. Secondly, multiply the top-left-hand digit by the bottom-right-hand digit (4*7), then add it to the top-right-hand digit multiplied by the bottom-left-hand digit (2*3), making a sort of criss-cross. Remember to add the 1! So (4*7)+(2*3)+1 = 35.

42                             3
37
-------
54

(carrying the 3) Do the same step as the first step but do it for the left-hand-side this time.

   42
   37
--------
1554
--------

I managed to do that in less then 2 seconds (1.8 seconds), and you should be the same after a long time of practising. See if you can figure out the pattern when you do it for 3, 4, 5, 6, 7, 8, 9, 10, 11 and even 12 digit numbers! Multiplied by 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 digit numbers! Of course, you can go on forever.