Math::NoCarry 1.10

Math::NoCarry is a Perl extension for no carry arithmetic.

SYNOPSIS

use Math::NoCarry;

my $sum = Math::NoCarry::add( 123, 456 );

my $difference = Math::NoCarry::subtract( 123, 456 );

my $product = Math::NoCarry::multiply( 123, 456 );

No carry arithmetic doesnt allow you to carry digits to the next column. For example, if you add 8 and 4, you normally expect the answer to be 12, but that 1 digit is a carry. In no carry arithmetic you cant do that, so the sum of 8 and 4 is just 2. In effect, this is addition modulo 10 in each column. I discard all of the carry digits in this example:

1234
+ 5678
------
6802

For multiplication, the result of pair-wise multiplication of digits is the modulo 10 value of their normal, everyday multiplication.

123
x 456
-----
8 6 x 3
2 6 x 2
6 6 x 1

5 5 x 3
0 5 x 2
5 5 x 1

2 4 x 3
8 4 x 2
+ 4 4 x 1
-------
43878
Since multiplication and subtraction are actually types of additions, you can multiply and subtract like this as well.

No carry arithmetic is both associative and commutative.