Math::BigInt is not very good suited to work with small (read: typical less than 10 digits) numbers, since it has a quite high per-operation overhead and is thus much slower than normal Perl for operations. But for some applications, you want fast speed for small numbers without the risk of overflowing. This is were Math::BigInt::Lite comes into play. Math::BigInt::Lite objects should behave in every way like Math::BigInt objects, that is apart from the different label, you should not be able to tell the difference. Since Math::BigInt::Lite is designed with speed in mind, there are certain limitations build-in. In praxis, however, you will not feel them, because everytime something gets to big to pass as Lite (literally), it will upgrade the objects and operation in question to Math::BigInt.