# Large Number Multiplication

This discussion is closed.
#1
Does anyone know any place on the internet where I can find a program to do multiplication for me? I need something that can deal with numbers that have more than 40 digits.

P.S. If you are really bored, can you help me to check that if

99988855898465431321564687561321321396325
*
2560565846542132165468798798454654362132
=
256028049448433401323739922204255255110212856688351728855362261630987506443964900
0
18 years ago
#2
0
18 years ago
#3
(Original post by Camford)
Does anyone know any place on the internet where I can find a program to do multiplication for me? I need something that can deal with numbers that have more than 40 digits.

P.S. If you are really bored, can you help me to check that if

99988855898465431321564687561321321396325
*
2560565846542132165468798798454654362132
=
256028049448433401323739922204255255110212856688351728855362261630987506443964900
Dude! I hope you don't do that for fun!!
0
#4
(Original post by theone)
The limit for longint is something in the 10^32 region, meaning that the largest whole number it can handle has 32 digits. Although real number is longer, but the answer it gives is not as accurate.

Any Ideas?
(Original post by Angel Lory)
Dude! I hope you don't do that for fun!!
I don't do it for fun. I just want to make sure that my Large Number Multiplier is doing the calculation correctly.
0
18 years ago
#5
(Original post by Camford)
Does anyone know any place on the internet where I can find a program to do multiplication for me? I need something that can deal with numbers that have more than 40 digits.

P.S. If you are really bored, can you help me to check that if

99988855898465431321564687561321321396325
*
2560565846542132165468798798454654362132
=
256028049448433401323739922204255255110212856688351728855362261630987506443964900
That's wrong according to Mathematica, which gives the result as:

256028049448433401323739922204255255110212856688351728855362261630987506443964900

Arbitrary precision integer multiplication is not difficult to write in a programming language such as C(++) or (God forbid, something like Visual Basic), just think about how you'd do long multiplication as a human and replicate it in a programming language.

If you don't have the necessary prerequisite programming skills, you have a few options, either acquire software such as Mathematica, Matlab or Maple (or there may be freeware software available for arbitrary precision arithmetic, I don't know). The Windows XP PowerToys calculator supports precision up to 512 bits which allows for numbers much longer than you have above. It's available from MS' site. Alternatively, I believe Java includes an arbitrary precision arithmetic package, if you have the Java skills to use it.

EDIT: It appears your calculation was in fact right, sorry.

I hope this helps,
0
18 years ago
#6
why dont you do it by the power of the mind? shouldn't be too difficult especially with such small numbers! lol y do u need to know anyway?
0
18 years ago
#7
Had to make a 60 digit calculator in computing last year...

PM me if u want it, ive got it lying about somewhere.
0
#8
Thanks for the reply. I guess that means I have something here can deal with numbers which give products of 2*1024^3 digits. That's one hell of a number...

Next stop. Square rooting large numbers.

P.S. Program written in Delphi (Pascal).

Had to make a 60 digit calculator in computing last year...
Never did such thing in computing...had to do something to differentiate polynomials though...
0
18 years ago
#9
i had to deal with large numbers while writing a combination of the enigma and RSA ciphers. i used an implementation in C++ called CLongInt<n>, where n is the number of bits. I had the source code somewhere, but I can't find it...
0
18 years ago
#10
I have been trying to implement this for a while now any idea on where i can start.
0
18 years ago
#11
Things like this are fun in mathematica, its just fun to do like 30000! just cos you can and end up with a number about 20 A4 pages long on size 12 font. Plotting 3d cylindrical spiarals using parametric coordinates is also fun, (sad i hear you call)
0
18 years ago
#12
(Original post by Camford)
Does anyone know any place on the internet where I can find a program to do multiplication for me? I need something that can deal with numbers that have more than 40 digits.

P.S. If you are really bored, can you help me to check that if

99988855898465431321564687561321321396325
*
2560565846542132165468798798454654362132
=
256028049448433401323739922204255255110212856688351728855362261630987506443964900
I have code/software and code that can multiply any number (any number of digits). contact me.. [email protected]
0
18 years ago
#13
why ot use gelosia on paper - it takes a little longer but is still pretty quick.
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