How to Multiply

There are several useful methods for multiplying.

This one is one of the most space-consuming, but is also one of the easiest, as it only requires you to know your tables up to 9x9.  This makes it especially useful for KS2 or less-able KS3 students (age 9+)

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Step 1: The grid method.

The method has several names, but is most often called the grid method.

To multiply two numbers together, the numbers are first broken down into their component place-value chunks.

For instance, let us multiply 47 by 68.

"47" is actually "40 + 7" and "68" is "60 + 8".

These numbers are written into a grid, as in the illustration below:

Step 2: Multiply the rows and the columns.

It's almost easier to show than describe.

Ignoring the zeros, multiply the digits at the top of the columns with those at the left of the rows.

4x6 = 24

4x8 = 32

7x6 = 42

7x8 = 56

Now we add the zeros back on - 24 gains a zero from the 40, and one from the 60, so becomes 2400.

Similarly, 32 becomes 320 and 42 becomes 420.

That's the hard part done.

All you have to do now is add up the four numbers in the grid. Remember to be careful about place value, and align them up to the right.

Step 4: You want more??

You've had the basics - this method can be extended to multiplying any two number of any length.

It is possible to use it to multiply more than two numbers, but you need to work them out as you go along (for example, 23x46x17 would need you to work out 23x46 and then multiply that result by 17).

You are not just limited to two-digit numbers - here are a pair of three-digit numbers worked out on a scrap of paper.
mynameisjonas5 years ago
great kiteman! is this a variant of the lattice method?
2 years ago
ok.can anybody explain me that how to salvemath problem for kids
Kiteman (author)  mynameisjonas5 years ago
No - that linked method looks like a variation of Napier's Bones.
Gjdj35 years ago
Nice! This is a really cool method.
Kiteman (author)  Gjdj35 years ago
It's supposed to be for kids who can't do the traditional "columns" method, but it is popular with all our kids, and I have even caught our head of maths using it.
4 years ago
I used this method for my maths GCSE yesterday - but I had been told it wasn't the 'right' way - so I did the other method next to it
Kiteman (author)  xilefakamot4 years ago
As long as both methods gave the same result...
4 years ago
They did ... luckily :)
aztennenbaum5 years ago
heh, when I was a kid, I never paid attention in class, and came up with my own way of multiplying that was very similar

96
x 47

42
630
240
3600

4512

I got points taken off for not doing it right :-(
Kiteman (author)  aztennenbaum5 years ago
The current policy in the UK in my school in my lessons is "if it works, it works".

I don't mind how you get to the right answer, as long as you know how you got there, and could get there again.
5 years ago
I normally find the right answer, then it runs and hides from me.
ReCreate5 years ago
You forgot If all fails, Just use a calculator.
skunkbait5 years ago
OoooOh! I thought this was an ible about unprotected......... Nevermind.
Kiteman (author)  skunkbait5 years ago
Sigh...
5 years ago
Leave it to the clergyman to make this about procreation!
Kiteman (author)  skunkbait5 years ago
(Maybe I could leave it to the clergyman to lead the voting?)
5 years ago
lol
SoapyHollow5 years ago
Wow, I've never seen it done that way. But then...I was a liberal arts major. ;)